Mario is Too Mainstream: Tim from Braid tries to act like he's so much better and more original than mainstream games like Mario and Zelda. Mario proceeds to utterly destroy every single point Tim makes about his game's originality. EX. Braid has time reversing abilities, Prince of Persia already did that. Braid has you collecting puzzle pieces? Banjo-Kazooie already did that too. The best part is how Mario wasn't even trying to debunk Tim's claims. If anything he was just making friendly conversation (it was Tim being all huffy and pretentious). He was just trying to point out that Braid was a good game that had familiar elements.
Mario & Luigi: Prank War: Luigi has suffered getting pranked by Mario and Toad not once, but twice. They try and prank him a third time, this time with the classic "Flaming Bag of Poop" prank... but he's caught on to their tricks by now, and he leaps through the roof in a Kuribo's Shoe, right on top of Mario, causing Toad to scamper:
What Would Happen If Peach Got Regular-Kidnapped, Peach is kidnapped by a much more menacing criminal who demands a huge ransom from Mario. Mario meets the kidnapper, who wants to look at the coins to make sure they are "legit", to which Mario mutters "Oh it's a legit and hits a P-Switch, turning all the coins into bricks. The kidnapper is subsequently crushed into a pile of gore.
Ski Free Yeti Gets Desperate has the infamous Yeti unable to catch the skier and trying increasingly futile ways to get him to slow down. Eventually the Yeti tries to use one of the jumps to get ahead of the skier, and gets fatally injured from the fall. For anybody with bad memories playing that unwinnable game, this is pure catharsis.