Big Lipped Alligator Moment: Performed an (admittedly sweet, once you get over the absurdity of it all) song about uniqueness on Yo Gabba Gabba!. Promptly never brought up by the band afterwards. Subverted in the case of the fandom, who do like to bring that up every now and again.
Epileptic Trees: A whole forest was planted before The Black Parade was released, resulting in lots of Wild Mass Guessing. Come to think of it, the forest might still be expanding, as there's no real agreement on whether it's the story of The Patient as he's dying or after he dies.
And now there's a whole new forest being planted surrounding the new album! This place has coverage on what's been going on.
Wouldn't it be Epileptic Cacti since the new stuff seems to be taking place in the desert?
Approximately 3 years later: that would be Danger Days, ladies and gentleman. Which is indeed set in the desert.
Memetic Mutation: Gerard will smash your face in for six bucks and a Dr Pepper. He'll also break into your house and suck your blood if you illegally copy I Brought You My Bullets, You Brought Me Your Love.
"My Gun fires seven different shades of shit. What's your favorite color, punk".
"IN A BAAAAAAAAAHHHHHWWWWWWKKKKSS".
"BUT THERE'S SHIT THAT I'VE DONE WITH THIS FUCK OF A GUN". Pointless, ridiculous, hilarious.
Narm Charm: The "Na Na Na" video and "Art is the Weapon" trailer.
Let's face it; MCR is made of Narm Charm. And it's fucking awesome.
Nightmare Fuel: Gerard's really rather good at this on stage, able to seem potentially Ax-Crazy before looping back into just Crazy Awesome or even badass. Song-wise, "Mama" and "Bury Me in Black" could qualify.