Jellyzappers are a species, or perhaps multiple species, of mutant jellyfish. They're most notable for their method of locomotion and hunting: filling their translucent bodies with a mixture of lighter-than-air gasses that allows them to emerge from the water and float in the air for hours at a time. They typically do this at night, so as to draw insects into their tentacles, attracting them with their bio-luminescent bodies. Singularly, their venom is not life threatening to adult humans, but they often congregate in large numbers. The lazily floating herds make little noise and can drift over a boat with ease if passengers are not vigilant.