Abra.
Teleport
Psychic
Protect
Theif/Trick
He'd live inside my backpack (with appropriate head, arm & leg holes), and we'd teleport around on criminal sprees. Teleporting into bank-safes and taking money.
Psychic for moving objects, and repelling security
Protect for any bullets/ attacks that may occur
Theif for any nimble moves to steal a delecate object
Trick for tricking guards/ owners of their possestions
Teleport for the obvious entering and escaping.
Probably have a Weezing on stand-by, to create a nice smokescreen too.