Waterbugs prey on people and animals near the shore on sunny days.
Right before a waterbug attacks, its shell starts to glow with a rainbowy light, so if you see a sudden glint beneath the water, you run. Those who are too slow get caught in the flash of blinding light as the waterbug launches itself out of the water. No one knows what happens then, as by that point any witnesses will have run for their lives.
Old wives' tales say that the waterbugs only feed on fish, and instead of devouring their victims, they drag them back to their nest to use as living hosts for their eggs. But of course, no one has ever come back after being caught in that flash of light, so who knows?
As a completely unrelated fact, for a telepath to come into contact with a sufficiently alien mind can cost a lot of sanity points. Someone who is not a natural telepath, but accessing telepathic powers through ritual, however, might not even realise that such an event has taken place.
