Elijah Wood as ['The Guy'](https://www.youtube.com/watch?v=aF_Ijr621tM) in Spy Kids 3-D. Maybe not *the* weirdest cameo but the first one I remember ever catching me off guard (because I only knew him as Frodo at that point, so seeing him in something where he wasn't talking like he was in a fantasy epic was strange).
Also, Tobey Maguire in the trailer for ["Satan's Alley"](https://www.youtube.com/watch?v=vuziQsUrbeM)
Cate Blanchett in Hot Fuzz
You literally only see her eyes as her hair and face are covered by a forensic suit
And she's in it for like 2 minutes
For me the oddest cameo would have to be either be...
Michael Jackson in the Men in Black Series as the agent stationed on the antarctic. The weird thing being how little they really used him and the fact that the king of pop even agreed to it.
Backstreet Boys in This Is The End namely because of how cameo heavy this movie was and they still stand out as the biggest surprise. Also they were part of what was surprisingly a fun ending (Something I didn't not expect.)
Mike Myers in *Inglourious Basterds*. I like Myers, I like that movie, but it was just surprising. But he's a huge fan of that type of movie and had always wanted to do it, so good for him.
i was not prepared to see hugh jackman in night of the museum 3.
The backstreet boys in "This is the end", when the music starts I was like -nah, no way... and Bam! Full Backstreet Boys reunion concert
James Franco in Alien: Covenant. To be fair I never watched the prologue on YouTube so just seeing an unidentifiable corpse and pictures of him later on in the movie was just so fucking hilarious to me. Like I could only see James Franco.
Hunter Thompson in Fear in Loathing in Las Vegas. "Holy fuck, there I am!"
David Hasselhoff in Guardians of the Galaxy vol. 2. Totally unexpected in a weird, entirely welcome kind of way.
George Clooney in South Park: Bigger, Longer, and Uncut
Bruce Willis AS HIMSELF in Ocean's 12
Maybe not the strangest but Bruce Campbell throughout the Sam Raimi Spiderman trilogy alsways surprised me as each cameo was a different character.