Paralysis is a magically-induced inability to move. Depending on the length and cause, paralysis can be quite dangerous, as monsters may get many free turns.
- Attacking a floating eye. If you can see it and your hit does not kill it, there is a 2/3 chance that you will be paralyzed for a large number of turns (usually d70).
- Attacking or being attacked by a gelatinous cube. This paralysis does not last as long.
- Being attacked by a shade, ghoul, guardian naga or Yeenoghu. This attack is affected by magic cancellation.
- Being hit by a thrown or wielded potion of paralysis. This will paralyze you for 1-5 turns.
- Drinking a potion of paralysis. This will paralyze you for 13-46 turns depending on BUC.
- Being attacked by the clerical spell paralyze.
- Being hit by Magicbane (one of the random effects).
You will likely encounter many thrown potions of paralysis throughout the game. In certain cases, such as when in crowded conditions on the Astral Plane, getting paralyzed for five turns can be deadly. The danger is so great that some players will even wish for a ring of free action if they have not found one by the time they reach the Astral Plane. If you have one, you should definitely wear it for the Sanctum and Astral Plane.
Most of the other causes of paralysis are easily preventable with good tactics. You can completely prevent paralysis from hitting floating eyes by not hitting them in melee unless you have reflection. Gelatinous cubes generally paralyze you for a short enough time as to not be dangerous unless you are in a crowd, but you can kill them with missile attacks if you're worried. Shade attacks are blocked by magic cancellation, so wearing a good cloak will prevent them from being a hazard. Finally, don't quaff unidentified potions that might be paralysis (price 300).
Monsters can also be paralyzed in NetHack, a prime example being when pets hit a floating eye. You can wake them up with nonmagical or uncharged drums or horns. In the case of floating eyes, zapping a wand of make invisible at the eye can help prevent paralysis.
You can also throw potions of paralysis at monsters, or wield them and break the potion over their head, to paralyze them. Beware of the released vapors that may paralyze you, though; a ring of free action will protect you.
A similar condition, helplessness, is caused by the following actions:
- reading a cursed spellbook (sometimes)
- chatting with a skeleton
- hurtling through the air by throwing something while levitating
- praying, although a successful prayer also renders you invulnerable for its duration
- quaffing a milky potion and producing a ghost
- entering a deserted temple and producing a ghost
- using a crystal ball
This state is identical to paralysis except for the fact that it cannot be prevented by a ring of free action or any other means. However, all means of inducing this state require some deliberate action on the player's part, so the state is always avoidable.