This is a Remora fish. It has a suction cup that can stick to almost anything. It sticks to fish like sharks to avoid predators and feeds off its host's poop. It's

Open Thread 317 - by Scott Alexander - Astral Codex Ten

A Cat is a Puzzle for which there is no Solution - ART FLAIR

Cute Pixelated Corgi #7 - PIXELATED CORGIS

That idea doesn't suck: Hitchiking fish inspires a robotic suction

Absurd Creature of the Week: The Fish That Wears a Suction Cup as

sharks – NOAA Teacher at Sea Blog

FAQs on Freshwater Aquarium Snail Disease/Health

bats Strange Animals Podcast

s Saltwater Aquarium e-Book

This Fish Has a Suction Cup on Its Head to Stick to Sharks

Absurd Creatures: That Fish That Suctions to Sharks? It's Actually

What Good Is Half a Sucker?