Babel effect
When one simple idea gets passed around like a hot potato and ends up being twisted into something completely stupid by everyone who touches it. It still has some connection to the original, but only if you squint really hard and curse a lot.
A teacher says, 'Write about your favorite memory.' A student writes a 50-page essay about a time they spilled cereal on their dog.
A meme starts as a single joke, then turns into a full-blown war between two sides of the internet.
A recipe for cookies gets changed to include ketchup, duct tape, and a live chicken.