No one said that monsters needed to be big or even scary. But when James Dwight Dana first spotted one strange plankton species back in the 19th century, he knew he had something weird on his hands. “Little monster,” Monstrilla seemed like as good a name as any. After all, scientists can name species after pretty much anything, even penises. A 2014 expedition to the Arctic revealed a whole new species of these little monsters hanging out beneath the ice.