Easy and quick!
What if the alien costume had possessed spider-man?
An original answer:
I used an old spider-man black costume figure (it is the same body that ml ice-man)and change his head to venom´s head (venom from sinester six box set). Later, I find a "mask" from the spider-man classics venom´s rubber face, and I though that adding it over his head I could get a more horrible spider-venom!
