Eel

Eels are serpentine fish that rarely look for trouble, though each kind has a nasty way of defending itself. The electric eel reaches 9 feet, with a smooth, scaleless body, two small pectoral fins and a long fin running along 80% of its belly that lets it dart in any direction, even backward. It is mostly dull gray, often with a vivid red or green patch on the throat and belly.

Whether hunting or defending itself, an electric eel releases a shock that fills a 15-foot radius: 3d8 damage to creatures within 5 feet, 2d8 to those 5 to 10 feet away, and 1d8 to everything else in range. It then needs an hour (six turns) to recharge. Toothless, it hunts frogs, fish and other small creatures it can stun and swallow whole. When defending itself, it flees while its attackers are still reeling. It is immune to electrical attacks.

Electric eels live alone in shallow, sluggish, warm freshwater rivers except when breeding. Whenever one discharges, 1-2 others nearby are 80% likely to come looking for a free meal.

Giant eels grow to 20 feet and have no electric discharge, relying instead on their teeth. Most live in warm seas, though 10% inhabit fresh water. They are bad-tempered and usually lunge out from a cave or crack in the rock.

These 20- to 40-foot sea giants are saltwater cousins of the electric eel, so quick that they gain +1 on initiative. Their 15-foot shock deals 6d6 within 5 feet, 4d6 from 5 to 10 feet and 2d6 beyond. Victims must also save vs. paralyzation or be stunned for as many rounds as the damage they took; distance helps, giving +1 at 5 to 10 feet and +2 at 10 to 15 feet. A successful save avoids the stun but not the damage.

Weed eels look so much like seaweed that even a trained observer spots them only on a 1 in 6. Their bite is poisonous: fail a save vs. poison and die in 1d4 rounds. They live 25 to 40 feet down in fresh or salt water in loose colonies of 10 to 60. Each colony centers on a cave roughly 30 feet long and 20 feet wide and high, its floor littered with scavenged pebbles, coins and gems, where the young are raised. Six-foot tunnels branch out from it into a maze of holes six to eight inches wide, each the home of a single eel. They defend the colony savagely, the nursery cave most of all.