The plop in the toilet sound has no single famous film or television origin, and it circulates mainly as a short user-shared effect for jokes and memes. Its appeal is simple recognition, as almost everyone knows the sound of something landing in water, so editors need no context to make the gag work. It is commonly found alongside other crude bathroom humour sounds in meme edits, reaction videos and short-form clips where a quick, silly noise works better than dialogue, and its short length keeps it useful as a fast punchline.