Who's The Most Hilariously (Or Painfully) Conceited Character?

You have to have a pretty high opinion of yourself to venture into space, or fight monsters, or try to take over the world. But some people's self-esteem is just too high. Who's the most amusingly (or annoyingly) conceited character in science fiction and fantasy?

Please include a picture or clip or book cover for this self-appointed paragon. And please mention his/her name, where he/she appears, and why he or she is so high on him/herself. Thanks!

Top image: Captain Hammer from Dr. Horrible's Sing-Along Blog, finally getting to join the Avengers, where he belongs. If you know who created this, please let us know!