'A globe of raw primordial fire, capable of impressive pyrotechnics, and of twisting the very flesh of creatures who come into its ken.'

A terrifying monster from Dungeon Crawl: Stone Soup. Unless you are decked in fire, these horrors will annihilate your character ( one of my high-level characters got killed in two turns ).

Plus they are fast, durable as hell ( high hp, immune to almost all elements ) and mutate you.

A quick mousedrawing I did.