Radscorpions

Radscorpions are horrific, giant scorpion creatures that evolved on Earth during the 700-year 'Great Exodus', during which Humanity vacated Earth to protect both themselves and the planet itself following the Fall of Lord Hood. Radscorpions eveolved in one of the most irradiated places on the planet and quickly spread across Earth, feasting upon Brahmins and Cazador and in turn being preyed upon by Deathclaws.

They were named by a totally uncool scientist who saw one and said 'They're so Rad!' Before being stabbed in the head, flailed around and thrown against a wall, dead. The Radscorpion's tail had never been seen to be used as a blade before and it sparked heavy controversy as to whether the species was bloodthirsty by nature, however the scientists had little time to debate this as the Humans called in their Elite buddies to eradicate the Radscorpions, save for a few that were preserved in Zoos.