Thanks to his fourth wall-breaking antics and his encyclopedia knowledge of pop culture (both in the X-Men universe and outside of it), Deadpool is a perfect terrain for cameos, if you think about it. The character knows no reverence and he likes to keep people on their toes, particularly through his fast-moving mouth. In that spirit, when it came time to make Deadpool 2, the original film's staggering popularity paved the way for a smörgåsbord of surprise guest appearances, including a few you might've missed!