Doing Carnage made me start thinking about symbiotes in the MU. Therefore: I present symbiote Spider-man.

After being teleported to Battleworld by the nearly-omnipotent Beyonder, Spider-man's iconic suit was damaged. He was told there was a machine that would create a new one for him. In reality, it was a prison for a symbiotic creature, which slid over him and, influenced by the design of Spider-woman's costume, took the form of a black spider-suit. It hitched a ride with Peter back to Earth, where it later bonded with Eddie Brock to become Venom.