The fusion of a human with several different arthropods. Most attempts at multi-species fusion end in a messy, lifeless failure, but a rare few have given rise to a creature of almost legendary proportions, the powerful and terrifying Chimerisect. This chitinous blob of gibbering mouths and twitching appendages exists in a state of perpetual spontaneous mutation, its limbs and organs regularly twisting into strange new forms, a living patchwork quilt of evolutionary memories and future possibilities. Claws, stingers, poison glands and sucking mouthparts erupt from its tumorous body at random, making it an equally dangerous foe from any angle.
A Chimerisect will consume anything organic, but seems particularly drawn to arthropods and other arthropoid monsters as prey, which are thought to strengthen its pool of potential traits. There are unconfirmed reports of these creatures emerging spontaneously from aging or malfunctioning fusion equipment, the residue of countless past experiments congealing into a new life-form.
There are now 51 human-bug hybrids in the world of Mortasheen, and I think I'd like it to keep it that way. I can't think of any other "bugs" quite famous enough to warrant inclusion, and I think this is the perfect number to leave them with; in my game concept, the Chimerisect would be your reward for having created all 50 of the others types