Traits

A strong tail with a suction cup-like extrusion on the tip for adhering to cave ceilings.
Cave leeches with this tail are ambush predators, and can hang in wait for weeks at a time in a partial hibernation state, waiting for prey to pass below. Tiny cave leeches will cluster together across an entire cave ceiling and rush their target as one, overwhelming it in an instant.
The larger the leech, however, the more vestigial this trait becomes as their body becomes too heavy to hold up for long amounts of time.