At the end of episode 5 of the Smash Brothers documentary, Revolution, PC Chris talks about the Double Dedede Theory. It goes like this: In the background in Dreamland in Melee (not Project M 2.6b because Dreamland is different) you can see Dedede flying in the background, and the theory goes that sometimes two Dedede's flying in the background at the same time... Surprisingly it's pretty common.
I saw Mewtwoking at Youmacon. He's one of the best smashers in the world or somefin, right? My friend may or may not have fought him in Melee, I left before the tourny was over. I'll have to ask.
I was also in the livestream, hehe. I wonder where the video for that is, if they have one.