A water moccasin, S, is a variety of snake, virtually identical to the normal snake but not generated at random. Like regular snakes, water moccasins will hide under items, are poisonous to eat, and have a 27% chance of imparting poison resistance, slightly higher than a snake (26%).
They are generated only in groups by quaffing from (or dipping an item into) a fountain (often killing unsuspecting low-level characters); their presence in the absence of fountain quaffing is indicative of bones or a rogue shapeshifter.
Due to their affiliation with fountain quaffing, they are the fourth most frequent cause of death on nethack.alt.org (next to soldier ants, jackals, and wands); it is common in the #nethack channel on Freenode, on hearing of a water moccasin death, to exclaim "Go team fountain!" in acknowledgement of this.
Indiviually, water moccasins are similar enough to snakes that they can be dispatched in a similar manner. However, on top of necessitating poison resistance, their decent speed and appearance in swarms will require efficient crowd control tactics, which may be further complicated if previous uses of the fountain caused pools of water to form.
Water moccasins are a species of venomous snake well known in the southeastern United States.
- See the encyclopedia entry for snake.