mbfirefly posted a photo:

Well, not really deadly. But their protein-based venom can cause extreme pain. I am speaking from a personal experience. Sting rays inject similar protein-based venom. I had a "pleasure" of stepping on one a few years ago. The level of pain was not something I ever experienced before or after. And I hope never will. An ambulance and emergency room followed, but I know better now. I did not blame the ray. It was my fault. I stepped on him and he had to react. I would have done the same thing if someone stepped on me. If I could... The lionfish in this picture, sting rays, jellyfish, all use similar protein-based venom when attacked. But they are beautiful and gentle creatures if you approach them with respect.