The SpongeBob Rainbow meme, often referred to as the 'Imagination' meme, originates from the 2002 SpongeBob SquarePants episode 'Idiot Box.' In the scene, SpongeBob explains to Squidward that he doesn't need a television because he can use his imagination, spreading his hands to create a magical rainbow effect. While the original scene was earnest, the internet transformed it into a versatile tool for sarcasm. It is frequently used to mock outlandish ideas, suggest someone is living in a fantasy world, or ironically explain how things work by replacing the word 'Imagination' with other captions.