Stan Lee likes to cameo in things. You may have noticed this. At this point, "The Man" has been popping up in Marvel films for decades, in everything from X-Men: The Last Stand to The Avengers. He also appears in this fall's Thor: Ragnarok.
SLIGHT SPOILERS AHEAD
As you may have noticed in the trailers, Ragnarok features Thor's trademark blond locks getting a serious trim. Early in the film the God of Thunder finally gets a haircut, under great protest, while being restrained on the planet Sakaar as he's being prepared for battle in the arena. The guy who gets to do the honors? Stan Lee, playing an elderly alien man whose hands are maybe not as steady as they used to be, wielding a crazy alien trimming device that justifiably freaks Thor out.
It's one of Lee's more memorable, and hilarious, cameo moments, so he decided he would re-enact it with Image Comics co-founder, Spawn creator, and former Marvel artist Todd McFarlane. Why? Well, that part's not clear, but Lee nevertheless grabbed a pair of scissors and pretended he was once again on Sakaar. McFarlane made sure to document the whole thing.
Again, it's still not entirely clear why this took place, but it's fun to see these two legends of the industry goofing around together. It's also fun to see that Lee, at 94, still has this much energy.