Peter Parker got his crime-fighting abilities as a result of being bitten.
Some see that as far-fetched, but this sort of thing definitely happens in real life as well.
For instance, if a rabid dog bites you, you get a rabid dog's ability to foam at the mouth.
It might not be the ideal super-power, but it should at least stop criminals from robbing YOU.
It might not stop the cops from coming after you, though.
Or at least animal control.
(That could be your super-villain name.)