Black Swallowers get their name from swallowing their prey, which consist of bony fish, whole. Now here’s where things get really weird – its food can be over twice the swallower’s size and TEN TIMES its mass!
Most specimens that have been recovered were found after undigested fish inside the [already dead] swallower produced gases that sent the sucker ballooning up to the surface of the ocean where it could be collected.
Thanks Jennifer Paul, for recommending this creature!