TIL that the manta ray has the biggest brain and by far the biggest brain-to-mass ratio of any fish and is one of the few animals in the world that may pass the "mirror test" for self-recognition.

Manta rays are incredible. I went swimming with them in Vietnam, they are like majestic flying pancakes. They are so much bigger than I expected them to be and they seemed to enjoy sneaking up to unsuspecting tourists with their crazy mouths and scare the shit out of them.