Cameos can come in various shapes and sizes – from Stan Lee’s blink and you’ll miss it Marvel appearances to Alec Baldwin’s blistering scene in Glengarry Glen Ross - but most of the time they’re just fun Easter eggs for audiences to discover while they watch the movie.
Some of the best cameos can even help elevate a movie or overshadow it completely, like Bill Murray’s surprise role in Zombleland taking it from being a fun horror comedy to near masterpiece - for about five minutes anyway.
One of the rarer types of cameo is an actor reprising one of their iconic characters, but appearing in a film outside of their original franchise. This mostly comes down to legal reasons – after all, icons don't come cheap these days – but they can be a nice surprise for even the most jaded movie fan when they happen.
Nearly all of these cameos are just tongue in cheek (and decidedly non-canon) appearances that aren’t meant to be taken seriously, and while some of them go unnamed in the movie, there’s little doubt about who they’re supposed to be playing.