A large gym rat
who picks on people much smaller than themselves. They use their bulging muscles to intimidate and get what they want. Often, their egos are as big as their muscles.
Mooley: "Get me a drink at the store, and no I don't have any money!"
Skinny guy: "You fucking mooley! If I wasn't half your size I would whoop your ass...but instead I'm leaving right now to go get your drink."