Pitching an idea...

[hider=Madcap]  He's another victim of the same messed-up doctor that created The Creeper.  His powers would be similar: superhuman agility, stamina, reflexes and (to a lesser extent) strength, along with something of a healing factor (taking minutes, not seconds to heal from serious wounds), and a paralyzing/fear-inducing manic laugh.  He'd also have the green hair, yellow skin, and distorted facial features.  He can change between "normal" and Madcap forms at will, but unlike The Creeper, Madcap prefers to stay in his powered form, as it beats the heck out of being the skinny little nerd he is without his powers.[/hider]