JAEKELOPTERUS RHENANIAE

Nothing about the words “sea scorpion” are comforting to begin with, so this should not come off as too awful: this was one of the two largest arthropods to have ever lived, reaching a length of over 8 feet of armored, clawed horror. Most of us freak out at the thought of inch-long ants and foot wide spiders, so it’s easy to imagine screaming like a little girl if you ever stumbled across a living one of these

On the plus side, sea scorpions (Euripterids) have been extinct since before the dinosaurs, having been wiped out in the Permian Triassic extinction event (which killed 90% of all life on earth) and are only survived, to some degree, by horseshoe crabs, which are even less formidable than regular crabs. There is no evidence that any sea scorpions were actually venomous, but the structure of their tail is similar to a modern scorpion’s, so it might have been.