The trench scorpion is distantly related to terrestrial scorpions. While most of the eurypterid sea scorpions of the Ordovician either went extinct or evolved to live on land, one species has remained in the inky blackness of the Mariana Trench where it has eluded scientific discovery until recently. This sea scorpion uses a bioluminous lure which grows on one of a pair of antennae. When the trench scorpion senses movement near the lure, it strikes with its venomous stinger and grabs its prey with formidable pincers. The creature has the peculiar habit of walking backwards on the trench floor, and since it has long ago lost its eyes in the black abyss, it looks very much as though its "tail" is actually its "head."