The evil coins are a group of monsters added in SLASH'EM. Their appearance is similar to a regular pile of gold coins with the exception of the regular pile of killer coins, making them somewhat similar to mimics. However the coins will still move and are not concealed, making it simple to identify them either by their movement or using the far look command. See also evil food.
Evil coins do not drop regular coins when killed, nor leave any sort of corpse.
Pile of killer coins
Large pile of killer coins
Huge pile of killer coins
Being "huge," this is arguably the largest of the 3 distinct piles of evil coins, perhaps even larger than the "large" pile.