3D

3D was the third member of Biff Tannen's high school gang. He earned his nickname because of his omnipresent cardboard red 3D glasses. (Back to the Future)

Original Timeline
3D would be a constant thorn in George McFly's side in high school, often assisting Biff Tannen. He would also present an obstacle of sorts to Marty McFly during Marty's second trip to 1955 by taking part in locking him in the back of a parked car at the Enchantment Under the Sea Dance. (Back to the Future Part II)

Biffhorrific Hill Valley
Around the founding of BiffCo, 3D would be hired as a bodyguard for Biff Tannen, the CEO. By that time period he had had traded his 3D glasses for a pair of tacky novelty sunglasses, albeit with red and blue lenses, similar to 3D glasses. (Back to the Future Part II)

3D would assist his boss, and thus Armus, by first capturing Marty and the Delorean time machine, but failed to capture the flux capacitor which Marty had hidden. Biff nearly fired him on the spot for his failing, and after his boss' rage, 3D sought to redeem himself in the eyes of his longstanding associates and his boss. (Star Trek: Voyager - Dark Realm)