[ i saw it, too...really liked Rocky raccoon (very dark :). ]
His Name is ROCKET and he doesn’t even know that he is a Raccoon...... Which is ironic...
He apparently was abducted from earth at some point by aliens and experimented upon both biologically and cybernetically and turned into a soldier....
Maybe an alien race needed foot soldiers but wanted to use a “dumb” and “easily replacable” biological entity that could reproduce fast ie. Raccoons... that they could modify and send into combat. Once they figured out how to do the process they could make them via assembly line fasion and they could use the cybernetics to control them. Rocket probably escaped as a “Prototype” and is not a Production model. Probably because he is a clever raccoon and they are good at escaping.
I loved Rocket’s sense of dark humor, and his “Parts” list for getting out of prison and later on...