The electric eel, ;, is a sea monster in NetHack. It is feared for being one of the creatures to possess a a two-move instadeath drowning attack. Its shock attack can also make rings explode, which is problematic for players using a ring of levitation to cross water.
Electric eels are most dangerous in the Plane of Water; in the rest of the game, eels cannot close to melee range so they can be rendered entirely harmless by not standing next to water until one has verified all the eels are dead (e.g. with telepathy or warning). Many properly prepared players still have a somewhat irrational fear of them; a charged wand of teleportation will reliably avert their drowning attack, a single blessed potion of levitation will carry you safely through the Endgame, and the especially timid can have the entire Plane of Water to themselves if they genocide all ; right after entering.
Electric eels are oviparous; if you polymorph into a female electric eel, you can use the #sit command to lay an egg.
South-American fish (_Gymnotus electricus_), living in fresh
water. Shaped like a serpent, it can grow up to 2 metres.
This eel is known for its electrical organ which enables it
to paralyse creatures up to the size of a horse.
[ Van Dale's Groot Woordenboek der Nederlandse Taal ]