The logo on the back of Terry's jacket is that of the Killer Dwarfs, a heavy metal band from the Toronto, Ontario area who were known for their offbeat sense of humor.
The small demonic minions are played by actors in rubber suits and were shot in forced perspective.
Terry's back patch when he's first seen is for the band Venom, who released the song "The Seven Gates of Hell" in 1984 on the b-side of their "Warhead" single.