Here are a few instances of WG and Inflations in fan-created animations based on video games (specifically parody animations based on old-school games rather than fan animations inspired by Super Mario Bros. Z and those taken down due to YouTube’s stance on sexual content):
In Mario’s Castle Calamity 1, Mario blows up after popping a Power Balloon in one skit, with him reappearing in this form in a later skit after his Power Balloon gas attack.
In a sort of blooper-reel video based on Super Mario World, Mario overinflates after touching too many Power Balloons and eventually gorily pops after coming in contact with a Spiny.
In a Flash animation on Newgrounds involving seven Mega Men representing each of the Seven Deadly Sins, one Mega Man is fat due to him representing the sin of Gluttony.
In a recent Super Mario Bros.-themed fan animation called Crazy Super Mario Bloopers, in the first skit, Mario hits a strange ? Block that has the M of the McDonald’s logo rather than the usual ? and comes in contact with the Big Mac that pops out of it, making him an immobile blob of fat, with Peach (the best one in the skit in my opinion, appearance-wise) already being just as obese as he is.
Those are all I have so far… As one of the forum goers on The Big Cartoon Wiki said on a thread like this, animations like those are goldmines for weight gain and inflation content.