Oh Cheese comes from Chikn Nuggit, the animated web series built around a small yellow dog-like character and his friends, where short, expressive lines are often clipped for memes. The phrase caught on because it is short, instantly recognisable and easy to drop over a visual gag. It spread through soundboards, short-form video and reaction edits, where creators use it to mark surprise, confusion or a sudden realisation. Its cartoon tone keeps it light, so it still works for everyday fails and playful edits.