They do not generally move to attack nearby prey, but their nearly translucent coloration makes it horrifically easy for a creature to swim into a swarm unawares. Once a jellyfish swarm deals damage to a creature, the swarm pursues it for several rounds before giving up the chase. Many aquatic races use jellyfish swarms as defensive guardians, trusting a swarm's lack of interest in moving to keep it stationary for long periods of time.