Dungeon fern (UnNetHack)

F dungeon fern
Difficulty	14
Attacks	Gaze 0d0 spores

F dungeon fern
Difficulty	14
Attacks	Gaze 0d0 spores
Base level	12
Speed	2
Base AC	10
Base MR	0
Alignment	0 (neutral)
Frequency (by normal means)	1 (Very rare)
Genocidable	Yes
Weight	20
Nutritional value	200
Size	Small
Resistances	None
Resistances conveyed	None
A dungeon fern: does not need to breathe. cannot pick up items. has no eyes. has no limbs. has no head. is mindless. does not eat. (*) is not a valid polymorphable form. is neither male nor female. is normally generated hostile. does not appear in Gehennom. does not appear in Sheol. never leaves a corpse. does not move normally, but can attack and perform other actions.
Reference	UnNetHack commit 4b5df73 - src/monst.c, line 3815

A dungeon fern, F, is a type of monster that appears in UnNetHack. The dungeon fern is a form of fungus-like fern monster with traits that are very similar to other fungi and molds, though it is stationary rather than fully sessile or fully motile.

Dungeon ferns have a "gaze attack" that causes them to generate dungeon fern spores with a ¹⁄₂ chance (50%) if they are not cancelled and the hero is within roughly 10 squares of one: these spores act as a means of reproduction for the fern and will target the hero and other monsters in the dungeon—monsters that are not other ferns, fern sprouts or Devil's Snare have a mutual grudge and will attack the spores themselves to prevent ferns from spreading, per the encyclopedia entry. Spores that explode from either their explosion attack or on-death explosion have a ¹⁄₃ chance of creating another fern, with a ¹⁄₆ chance of creating a full-grown dungeon fern and otherwise creating a dungeon fern sprout—their active explosion attacks also leave behind poison clouds.

Generation

Randomly generated dungeon ferns are always created hostile, and will not normally appear in Gehennom or Sheol. They are not a valid polymorph form. Dungeon fern sprouts can grow up into dungeon ferns.

Dungeon ferns can only be generated on normal floor squares or muddy swamp squares by normal monster creation or the explosions of their spores.

A "fern nursery" random vault has a ¹⁄₄ chance of randomly placing a hostile dungeon fern within the room.

Dungeon ferns never leave a corpse upon death.

History

The dungeon fern and its spore first appear in version 5.1.0 via commit 3aaf76d, and its sprout first appears in version 5.1.0 via commit 76bc877.

Origin

Ferns are a group of real plants with characteristic leaves. They are primitive, having neither seeds nor flowers; they reproduce with spores, hence the spore attack in the game.

Encyclopedia entry

These dreadful weeds have been driven to extinction on the
surface, yet deep within the dark and damp of the dungeon
they still flourish. When it detects the motion of nearby
creatures, the dungeon fern releases a deadly, poisonous
spore, which quickly detonates to propagate the species.

Residents of the dungeon have learned how not to disturb
the dungeon fern, and will attack its spores on sight to
keep them from overtaking their home.

More than one variety of this plant is known to exist.