For Your Consideration: Conan O'Brien's Sharktopus vs. Pteracuda Scene
Conan O'Brien may be the biggest human star in Sharktopus vs. Pteracuda, but he doesn't get a ton of screen time in his cameo as a slightly more dickish version of himself. Perhaps the producers were concerned that, if cast in a longer role, he would compete with Sharktopus for the spotlight and overshadow poor Pteracuda completely.
But, being the great thespian he is, Conan did was what necessary for the good of the picture, and died an early (and gruesome) death. Some days you chew the scenery, and some days the scenery chews you.