Super Chick Sisters

PETA made this Flash game featuring Mario and Luigi expies Nugget and Chickette, respectively, on a quest to rescue PETA spokeswoman Pamela Anderson.

Not to say that Mario and Luigi don't show up in these games, because they do, usually as the Butt Monkeys. There's also the blatant trademark infringement on Nintendo characters, though that might also qualify for a fair use exemption as parody.

The first game can be found here and its sequel, New Super Chick Sisters, can be found here.

Tropes

 * Artistic License Biology: In New Super Chick Sisters Nugget and Chickette have mustaches...despite being chickens...and female.
 * Author Tract: It's PETA. 'Nuff said.
 * Bound and Gagged: Pamela Anderson's condition before you rescue her.
 * Butt Monkey: The Super Mario Bros., especially Mario, in the first game.
 * Disproportionate Retribution: Mario suffering "Wiitis" and getting slapped by Princess Peach over a photo of Pamela Anderson are tame compared to getting beat up by PETT protesters for stomping on Koopas.
 * Enemy Mine: The Mario Bros. enlist Bowser's help in New Super Chick Sisters.
 * Getting Crap Past the Radar: If the occasional pools of blood don't get you or the fact Mario's license plate says MustacheRide, perhaps Bowser's mention of the R-rated movie Barb Wire as his motivation to help the Mario Bros. rescue Pamela Anderson will.
 * Informed Attractiveness: Pamela Anderson.
 * Monster Clown: Ronald McDonald in New Super Chick Sisters
 * Off-Model: The designs of Luigi and Bowser are based on how they appeared in Paper Mario and Mario & Luigi: Bowser's Inside Story respectively, though they are not accurate. Mario and Peach are derived from their Paper Mario appearances as well, and are mostly accurate, but their backsides are another story.
 * Plagiarism: Besides the obvious, several of Bowser's lines in the sequel are cribbed wholesale from Super Mario RPG.
 * Revenge Fic: These four YouTube videos.
 * Take That: Poorly disguised as Affectionate Parody. Making a joke out of the number of Mario Sports titles is one thing, going out of your way to reference Mario Paint and Mario Teaches Typing is another.
 * The Unfought: The Hamburglar in New Super Chick Sisters.
 * You Don't Look Like You: Ronald McDonald's character design changes between his first appearance and the boss battle.