Swimmer

A swimmer is any monster that has the  flag set. Attacking a swimmer with a trident while it is in water gives a +4 to-hit bonus.

Individual monsters

 * baby crocodile
 * crocodile
 * gremlin
 * mail daemon
 * newt
 * rust monster
 * water demon
 * water elemental
 * water nymph
 * water troll
 * woodchuck

Entire classes

 * all snakes:
 * cobra
 * garter snake
 * pit viper
 * python
 * snake
 * water moccasin
 * all sea monsters:
 * electric eel
 * giant eel
 * jellyfish
 * kraken
 * piranha
 * shark

Unique monsters

 * Medusa
 * Orion