He has a hand growing out his back and a eye on the back of his head.
He is good at watching his back with a pistol or shield.
It is very difficult to sneak up to him from behind.
He has a extra eye located in the palm of his hand.
This is good for peeking around corners and out of hiding without beeing detected.
He has fingers instead of toes on his feet.
This makes him good at climbing and hanging upside down from branches, where he can trow stuff at people below.
He has a hand between his legs.
With this he can steal stuff unnoticed from other people’s belts (grab purses etc.) and put it in his pants.
He can also easy get rid of itching in the crotch area.
Additional Ideas (4)
He has ball and socket joints in his fingers, toes, knees and elbows. Not only is the much greater range of motion really useful for scratching those difficult-to-reach places on his back, but it enables him to walk backwards fairly easily, contort himself into extremely difficult positions, and win countless bets in bars. As a side-note, his knees are almost impervious to pain, having been almost completely replaced with scar tissue from countless falls while learning to walk.
He has two bulging orbs protruding from his face. Each one has the ability to rotate freely within it's socket,allowing him to gain unrestricted observation of his suroundings from any angle,much like a chameleon's. Another useful physical attribute is the long and adhesive tongue that usally lies rolled up in his mouth,but is ever ready to shoot out like a rope of sticky fly-paper to trap whatever tasty morsel the mutant feels like dining on
Mutant may develop a distinctive pot-belly to accommodate the additional organs.
Advanced Digestive System - Mutant is able to derive nutrition from any non-corrosive carbon-based compound (ie. Crude Oil, plastics, etc).
Exotic Digestive System - Mutant is able to derive nutrition from bizarre chemical compounds -Chemosynthesis - any which contain chemical energy (eg. Hydrogen Sulfide) . Will require additional mutations to protect the body from the effects of such chemicals.