10 Bizarre Cameos In X-Men Comics
9. Darth Vader
Star Wars comics are published by Marvel, so perhaps Darth Vader's appearance on this list isn't the strangest, but it is definitely worth mentioning. And to beat this criticism to the punch, yes, technically Vader himself hasn't actually appeared in the comics, but his costume certainly has!
Back in Uncanny X-Men #155, Kitty Pryde tests out a costume creation machine that apparently was just lying around on a Shi'ar spaceship, because of course it was. After a montage of costumes Kitty tries on a Darth Vader suit, much to Nightcrawler's apparent worry (who would have guessed Nightcrawler was so mindful of copyright infringement).
This has no real bearing on the plot and nothing of consequence really happens because of it. It's just a cute little scene in a time period where both X-Men and Star Wars were relatively new and hot pop culture franchises. 80s X-Men references pop culture icons a lot in this manner and it's always nice to see one beloved franchise show respect to another, even if it is only for a brief panel.