Green Goblin x The Joker + Story

The Gremlin’s Origins by MoonKnightFan101:
Norman Napier was the CEO of chemical company which secretly produced super-soldier serums for the highest bidder. When Darkclaw and Nightspider came to investigate one night, Normans alarm went off and he saw the intruders through his security system. Seeing how the heroes beat his guards, Norman tried to fend off Darkclaw and Nightspider himself, but ended up tumbling over a fence when Nightspider approached him with force. Norman fell into the vat of experimental super-soldier formula and got mutated into clown faced freak with pointy ears. Normans mind fractured and his body was hardended, knowing he'll never be the same, Norman named himself after the creature of his childhood nightmare, The Gremlin, swearing vengeance against the Darkclaw and especially his young protege, the Nightspider.

Both characters belong to Marvel and DC respectively.