Worst cameo in a movie?

His cameos in Sixth Sense and Unbreakable weren't too bad, but everything about Signs was bad, especially his cameo, and it was all downhill from there.

That one speaks for itself.

Richard Pryor in "Superman 3"

I'm joking! How about Jim Belushi in "Abraxas: Guardian of the Universe?" His brief appearance was the best thing in it. Not a cameo per se but comes off as one.

The ark's in "Kingdom of the Crystal Skull" because it reminded me of a much, much better piece of pulp nonsense I'd rather be watching.

The only thing that I recall in Mary is him getting his dick stuck in his zipper, so you may be right. A football player who can’t pronounce his own name properly, and who does not insist on having others (ESPN morons) pronouncing his name—fav’-re, NOT farv—is a piece of useless, illerterate trash.

too big a part to be considered a cameo

Quentin Tarantino in "Django Unchained."