This bubbling effect comes from Donald's Tire Trouble, a Donald Duck short released on 29 January 1943, where exaggerated cartoon sounds were used to make everyday mishaps feel slapstick. The brief gurgle and pop fitted the era's hand-drawn comedy, when water, splashes and sudden surprises were given a playful, unreal sound rather than a realistic one. It later circulated as a stock cartoon effect, which is why the same bubbling pop turns up in edits, memes and short animations today, instantly signalling an old-school cartoon splash without needing any dialogue.