A sea creature called
the blue dragon:
1.) Is absolutely beautiful, with blue-and-silver camouflage that help it blend in to the ocean surface, where it floats
2.) Preferentially preys on the hideously poisonous jellyfish known as the Portuguese Man O' War
3.) Instead of digesting the nematocysts (the poison cells) of the jellyfish,
stores the poison cells in its colorful fringes, to a concentration level that makes them extremely dangerous to touch.
Easy enough to avoid, right? I mean, they're just camouflaged critters that float aimlessly on the ocean surface in warm waters.
Man, no wonder fiction is full of god-killers. There's always something that eats the next thing.