3-D (Casey Siemaszko), in Back to the Future I/II , is a member of the Biff Tannen gang. He's the one who sports the 3-D glasses, even though he hasn't a 3-D movie to watch. (In Hell Valley he sports the polarizing glasses that are the updated version in 1985.) His other two pals are Skinhead and Match.In a confrontation with Marvin Berry, 3-D is the guy who calls Berry a spook and tells him to stay out of things that don't concern him. That remark brings out the other members of the Starlighters band, who take exception to that remark.