It's a forum game but...

[Polymorph]

...every Match Game video on YouTube plays, but every time there's a stupid answer...

 

[Princess Céline]

It's a speedrun of Super Mario 64, but every time Mario jumps...

 

[Polymorph]

...A Mario 64 LP plays but every time an enemy appears...

 

[Lord Bowser]

...the binding of isaac intro plays, but every time "isaac" is said...

 

[DragonFreak]

...the binding of isaac intro plays, but every time "isaac" is said...

...The Isaac of Isaac: ReIsaac plays, but every time that video says Isaac...

 

[Lord Bowser]

...the binding of isaac intro plays, but every time "isaac" is said...

...The Isaac of Isaac: ReIsaac plays, but every time that video says Isaac...

...every tearsofgrace video on boir plays, but every time he shoots a tear...

 

[Xiahou Dun]

...cutscenes from the Subspace Emissary play. Every time you see Kirby...

 

[Lario]

... it zooms in rapidly onto his face and then it cuts to footage of the American woodcock. However, every one of its calls is replaced with...

 

[Polymorph]

...a Kaizo Mario 64 speedrun but every time the player earns a star...

 

[TPG]

Every SiIvagunner video plays but every time the Grand Dad motif plays...

 

[DragonFreak]

...every Flinstone episode is played, but every time Barney's name is said...