Any oversized mode of rapist transportation. For example, a rape school bus or rape tractor. Generally containing various chains, ropes, candies for the kids and binoculars for finding your victim.
Holy shit look at that school bus... the windows are all blacked out and there's some creepy bastard driving it with his penis out. That's gotta be a Rape-a-saurus Rex!
When laying in bed cuddling your partner, and one arm gets trapped under both bodies/pillow rendering it useless, it is 'T-Rex Arm', i.e completely void of movement and use.Thus, similar to a Tyrannosaurus rex's arm.