Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6
If a vampire bat goes 2 days without drinking blood, they can die. However, well fed female bats will puke up blood and share it with other bats that they like in exchange for grooming.
13
Sniffologists have the job of sniffing armpits.
4
A banana slug can be 6-8 inches and their erect penis can be just as long. Also, their penises emerge from their heads. After sex, banana slugs eat each others penises.
17
There's a phone app called RoboRoach that allows you to remotely control a cockroach through a chip that you to manually implant into the unwitting critter.
10