Boulder
- For the option, see option#boulder.
| Item classes | ||
|---|---|---|
| " Amulets | [ Armor | |
| % Comestibles | $ Coins | |
| * Gems | ! Potions | |
| = Rings | ? Scrolls | |
| + Spellbooks | ` Statues | |
| ( Tools | ` Boulders | |
| ) Weapons | / Wands | |
A boulder, `, is a type of huge stone object that appears in NetHack. Although boulders are considered items, they are large enough to block line of sight, and are too heavy for you to lift normally. As such, they tend to resemble a dungeon feature more than an item in practice.
The boulder symbol is customizable through the boulder option; many players choose to change the symbol for boulders to make them more noticeable. 0 (zero) is a popular choice.
Contents
Generation
Boulders are usually randomly placed during level creation, and are generally found in corridors or as part of rolling boulder traps.
Reading a scroll of earth will cause one or several boulders to fall; if read while confused, several rocks will fall. Reading an uncursed scroll will cause one to fall in each square around you and on you, and reading a blessed scroll omits the boulder that would land on you - reading a cursed scroll causes a single boulder to fall on you. Monsters can also read this scroll with the same effects.
Sokoban is a dungeon branch dedicated to puzzles where boulders are used to fill pits, and is usually the reason for many players using the aforementioned boulder option - Luck penalties are usually assigned for creating or breaking boulders in this branch on an unsolved floor. See the article or the section below for more information.
Polymorphing statues will sometimes produce boulders. Boulders can be wished for one at a time, but unless you are in the form of a giant or titan, the boulder will immediately be dropped to the floor.
Monsters
Dwarves wielding pick-axes or dwarvish mattocks and other NPC monsters that dig around a level will leave behind boulders on 8.3% of diggable rock.[1]
Non-undead giants and titans that are randomly generated have a 1⁄2 chance of being given a boulder.[2]
Description
You and other monsters cannot attack through boulders, but can use missile weapons, wands, and spells to attack through them. A pick-axe, a dwarvish mattock, or a force bolt (from the spell or a wand of striking) will shatter boulders and leave behind several rocks (specifically 6 + d60)[3] - other wands, weapons and spells, particularly the wand of digging, will have no effect on the boulder. Monsters will not target a wand of striking at boulders intentionally, and typically do so as a side effect of targeting you.
A spell of stone to flesh turns a boulder into a huge chunk of meat, which is a much less heavy object (though still quite heavy) with none of the boulder's unique properties.
Boulders and giants
Non-undead giants (including titans) can move over boulders, pick them up and even throw them. You can do the same if polymorphed into a giant. Boulders in a giant's inventory have no weight, as opposed to the 6000 aum they would weigh otherwise; you can pick one up while in giant form even if all other inventory letters are in use, and it will be assigned a hash mark inventory slot (#, also used by loadstones).
If a giant throws a boulder at you, it will land on your square regardless of if it actually hits you - you may move off the square as normal, but attempting to re-enter the square will require pushing the boulder out of the way. If you have displacement, or you are invisible and the giant throwing the boulder cannot see invisible, a thrown boulder that misses will instead land at the square where the giant thought you were.
Rolling boulder traps
A rolling boulder trap consists of a trigger square and a single boulder placed out in the open, usually in the same room as the trap; if you or another monster steps on that square, the boulder will roll towards the square to the other side, usually hitting that monster and anything else in the boulder's path. The boulder will stop rolling if it runs into something that obstructs it - a boulder that crashes into another boulder will send the second boulder rolling a short distance.
A rolling boulder will always move in a way such that it ends up on the opposite end of the trap at an equal distance away (e.g., a boulder 3 squares to the left of the trap will roll until it is 3 squares to the right) - the trap can set a boulder rolling from any side of it as long as it is a certain distance away, and will do so on repeated triggers if the boulder is not obstructed.[4] A boulder trap will not trigger its boulder to roll if it is moved off either square by anything other than the trap itself, or else disappears midway through rolling - e.g., if the rolling boulder fills a pit, hole or trap door, runs into another boulder or obstruction in its path, or it is caught by a giant that was in the way. Stepping on a rolling boulder trap that cannot trigger a boulder will cause the trap to disappear with no other effect.
Moving boulders
You (and other non-giant monsters) cannot travel past boulders without phasing - if you try to move onto a square containing a boulder, you will push it to the next square in line if possible; if there is more than one boulder on that square, you will try to push each boulder in turn until one of them does not move.[5][6] If you are riding and try to move onto a square with a boulder, your steed will push the boulder.[7]
Boulders that have a wall or other obstruction such as a monster in the direction you are pushing will not move; this does not use up a turn. You can "squeeze" through onto the same square as an obstructed boulder if you are not on a steed and either have an empty inventory (not counting any gold) or are at least 850 units below your carrying capacity.[8] Pushing boulders exercises strength. You cannot push any boulders if you are levitating due to lack of leverage;[9] you also cannot push boulders if you are a in a tiny-size form, though you can still squeeze past them.[10]
Pushing a boulder into a hole, trap door or either type of pit will usually plug it and turn that square into normal floor[11][12] - objects in a plugged pit are buried, while objects on or near a hole or trap doors's square may be knocked through before it is plugged.[13] A boulder that is pushed, rolled or thrown into a moat will fill it 9⁄10 of the time and create a floor tile that you can move across, and the remaining 1⁄10 of the time it will disappear with a splash that wakes up monsters.[14][15] This probability is reversed for lava, which causes the boulder to fill the square only 1⁄10 of the time, and disappear otherwise - lava will splash onto you in either case, which deals 3d6 fire damage to you, burns away any sliming and wakes up monsters;[16] fire resistance reduces this to d6 damage, and the damage can also be reduced by the half physical damage property.[14][17]
Boulders have a 3% chance of falling through a down stair if another thrown object lands on their square; this includes gold, but not rocks and gems.[18] You can also push them onto a teleport trap or level teleporter, though there is a very low chance of it landing on the down stair's square.
Sokoban
Sokoban is a branch with special rules for boulder pushing. Namely, you cannot push boulders in Sokoban diagonally until a floor is cleared. [19]
Additionally, there are Luck penalties for doing certain actions, if the floor is not yet solved:[20][21]
- For squeezing past boulders
- For moving onto or picking up boulders
- For breaking, polymorphing, or casting stone to flesh on boulders
- For creating boulders with a scroll of earth
Boulders and other traps
A user has suggested improving this page or section as follows:
"Account for trap doors, land mines and some other interactions."
While boulders can be used to fill holes and pits (including spiked pits), the exact interactions and effects depend on a few factors, including: whether the boulder or the pit/hole occupied the square in question first; the source of a boulder that is moved into a pit or hole; the source of a pit or hole that occurred in a square with a pre-existing boulder; and where you are standing in relation to the pit or hole.
Pushing a boulder into a pit or hole removes the boulder and the plugged trap, regardless of whether or not its location was known to the player character; items on the square of the pit are buried, while objects on or next to a hole's square may be buried or knocked through.[13] Boulders that land on the square of a pit or hole as a result of being thrown, dropped, sent from the sky by a scroll of earth, or else rolled via boulder trap will plug that trap and remove it, burying items as normal.
If you are trapped in a pit and a boulder is dropped or rolled in on top of you, the effect varies depending on if you are a giant or not. If you are a giant, the pit is filled and you are instantly freed from it without any further effect - if you are not a giant, the pit will not be filled, and there is a chance during each attempt to escape the pit that it is filled by the boulder, leaving your leg is stuck in a leftover crevice that you must pull free from. Zapping a wand of teleportation down or applying it while the boulder is still on that square will teleport it elsewhere, allowing you to try escaping the pit as normal. Holes that are filled while you are on their square will be plugged, just as if you were standing next to that hole.
Applying a charged drum of earthquake can create a pit underneath a boulder, which immediately fills the pit and also buries every item on that square underneath it[22] - interestingly, if there are multiple boulders on that square (e.g., usually from a giant dropping them all at once), they will also be buried, minus the boulder that fills the pit. If you are on top of a boulder and zap a wand of digging down on that square, you will create a hole or pit depending on the whether the level is diggable, and the trap is plugged immediately before anything can fall through or into it.[23] If a boulder is already present on a square with a pit, and you manuever into that square and zap a wand of digging down, the boulder will fill the pit instead of creating a hole, with two different messages possible.[23]
Though lacking any practical use, it is possible to get a boulder on top of a pit or hole outside of wizard mode: Drop a statue on top of the square via levitation, or by avoiding falling into the pit or hole when moving onto its square (which occurs with a 1⁄5 chance).[24] If you then polymorph the statue into a boulder, it will drop into and fill a pit, but not a hole - throwing other objects at a boulder that is placed on the same square as a hole in this way will cause it to fall through the hole and land on a lower level, as with boulders on a downward staircase.
You cannot dig down with a pick-axe while on a square with a boulder, and breaking a wand of digging will not create a hole or pit under a boulder - both are due to special checks in the code.[25][26]
The following information pertains to an upcoming version (3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.
Account for cases affected by commit a18859d - monsters that zap a wand of digging downward on an undiggable floor create a pit just as you do, and will usually fall into it immediately.Strategy
A user has suggested improving this page or section as follows:
"Expand this/other sections if possible."
Boulders are often used to protect stashes or polytraps by pushing one on top of the desired square; boulders can also be arranged around a square as a "fort", usually by reading a non-cursed scroll of earth, and blessed scrolls are best for avoiding taking damage in the process. A "boulder fort" can be used to keep most monsters away, minus hostile giants and phasing monsters like earth elementals.
Tactics for pushing boulders
In the diagrams below, the # represents where the boulder will move.
If there is no space or if it is occupied by a monster (whether hostile, peaceful, or your pet) then you cannot move the boulder in that direction. Failing to push a boulder will not consume a turn. If your inventory is mostly empty, you can squeeze onto the square containing the boulder. (The fastest way to drop your inventory is to press D and then choose option "A" to drop all items.) Such squeezing is useful if there is a door, hidden space, or boulder on the other side.
If a monster blocks the other side and will not move away, you have the option of squeezing onto the boulder and fighting it bare-handed and naked, or you can throw ammunition or Mjollnir or zap wands past the boulder. Be careful when doing so if you cannot see your pets, as they may be the monster blocking you or directly behind it. The player below might want to toss darts, rocks, or other objects at whatever is blocking the way to some holes ^ in Sokoban.
You can move diagonally around boulders (but not in Sokoban) regardless of how much you are carrying. So the following boulder does not block your path provided that you know how to use [yubn] or numpad to move diagonally:
##`##
If a boulder is blocking a corridor, and if you are able to push it into a room or into a position like the above, then you can walk around it.
When faced with two consecutive boulders in a corridor, as shown below, you can squeeze past one to push the other.
However, wandering around naked with no wielded weapon, or allowing hostile monster to take from your inventory, might put you in too much danger. You might want to push the other boulder and retrieve your inventory quickly. (The fastest way to retrieve the inventory is to press @ to toggle autopickup on and then move onto the square where you dropped it. Then you might want to press @ again to toggle autopickup off.)
Boulders, like anything else, cannot pass diagonally through open doors. If you need to do that, destroy the door by closing it with c and then kicking it down with Control-D.
The two boulders below are stuck against a wall, and you may only push them in two directions:
|...`.....| |....| -------
|.........| #####..`...####......|
|.........| # ------ |.....|
---.------- ### -------
If a boulder becomes stuck in a corner, then you can not move it at all, even if you squeeze onto its square (unless you are able to dig around it). In Sokoban, a 2x2 square of four boulders (or a 2x2 square of both boulders and walls) is almost likewise stuck, but you might be able to squeeze yourself to free the boulders. (Squeezing causes a luck penalty in Sokoban.) Outside of Sokoban you could have freed a boulder by moving it diagonally, but not if you have two boulders stuck against the same wall.
An example of stuck boulders:
---- ----
|`.. .``.
|... ....
An example of boulders that are stuck only in Sokoban:
...... ...|..
..``.. ---`..
..``.. ..``..
...... ......
Be very careful in Sokoban to not stick boulders in the above manners unless you are able to solve the level with the remaining boulders.
Variants
SLASH'EM
In SLASH'EM, rays from the spell of dig or wand of digging will vaporize boulders.
Tiny monsters can squeeze past boulders, and certain hiding monsters such as cave spiders and snakes can use boulders to hide.
GruntHack
In GruntHack, player giants can move over and pick up boulders as other giants can.
SlashTHEM
In addition to SLASH'EM changes above, SlashTHEM has ceiling collapse traps that may drop several boulders and rocks on and around the trap, possibly dealing high damage and killing even a well-kitted character even if they are wearing a hard helmet.
SlashTHEM also has player giants, with the ability to move over and pick up boulders similar to vanilla. hunger hulks are monsters that can tunnel similar to umber hulks in vanilla, but leave behind huge chunks of meat in place of boulders.
EvilHack
In EvilHack, boulders are stackable, and weigh 6 aum for player giants in order to prevent them from amassing an endless amount of boulders.
Encyclopedia entry
I worked the lever well under, and stretched my back; the end
of the stone rose up, and I kicked the fulcrum under. Then,
when I was going to bear down, I remembered there was
something to get out from below; when I let go of the lever,
the stone would fall again. I sat down to think, on the root
of the oak tree; and, seeing it stand about the ground, I saw
my way. It was lucky I had brought a longer lever. It would
just reach to wedge under the oak root.
Bearing it down so far would have been easy for a heavy man,
but was a hard fight for me. But this time I meant to do it
if it killed me, because I knew it could be done. Twice I
got it nearly there, and twice the weight bore it up again;
but when I flung myself on it the third time, I heard in my
ears the sea-sound of Poseidon. Then I knew this time I
would do it; and so I did.
References
- ↑ src/dig.c in NetHack 3.6.6, line 1328
- ↑ src/makemon.c in NetHack 3.6.6, line 183: Special case for titans and most other giants
- ↑ src/zap.c in NetHack 3.6.6, line 4720
- ↑ src/dig.c in NetHack 3.6.6, line 1771
- ↑ src/hack.c in NetHack 3.6.6, line 105
- ↑ src/hack.c in NetHack 3.6.6, line 302
- ↑ src/hack.c in NetHack 3.6.6, line 310
- ↑ src/hack.c in NetHack 3.6.6, line 367
- ↑ src/hack.c in NetHack 3.6.6, line 124
- ↑ src/hack.c in NetHack 3.6.6, line 371
- ↑ src/hack.c in NetHack 3.6.6, line 210
- ↑ src/hack.c in NetHack 3.6.6, line 224
- ↑ 13.0 13.1 src/dokick.c in NetHack 3.6.6, line 1537
- ↑ 14.0 14.1 src/do.c in NetHack 3.6.6, line 60
- ↑ src/do.c in NetHack 3.6.6, line 90
- ↑ src/do.c in NetHack 3.6.6, line 106
- ↑ src/do.c in NetHack 3.6.6, line 111
- ↑ src/dokick.c in NetHack 3.6.6, line 1431
- ↑ src/hack.c in NetHack 3.6.6, line 145
- ↑ src/hack.c in NetHack 3.6.6, line 361
- ↑ src/hack.c in NetHack 3.6.6, line 374
- ↑ src/music.c in NetHack 3.6.6, line 332
- ↑ 23.0 23.1 src/dig.c in NetHack 3.6.6, line 816
- ↑ src/trap.c in NetHack 3.6.6, line 942
- ↑ src/apply.c in NetHack 3.6.6, line 3417: Breaking the wand calls
dig_checkin dig.c - ↑ src/dig.c in NetHack 3.6.6, line 226:
dig_checkchecks for boulders here;do_earthquakeis music.c does not call this function
