The 'You've Heard of the Elf on the Shelf' meme is a popular wordplay format that emerged as a spin-off of the 'Elf on the Shelf' Christmas tradition. It typically consists of a setup line followed by a visual or textual punchline featuring two things that rhyme, often in a nonsensical or punny way. The trend took off on platforms like Twitter and Reddit around 2017, evolving from simple rhymes like 'Ash on the Trash' to increasingly complex and niche references. Its enduring popularity stems from its flexibility, allowing users to showcase their creativity and linguistic wit through absurd, rhyming juxtapositions that range from wholesome to surreal.