I can’t find the original anymore, but it was called “Look at this dude”, and featured a guy putting ketchup on the top of another dude’s head in a mall food court, then dipping a fry in it and eating it. The camera guy is narrating with the laugh that I’m sure is the one you’re talking about, and he says “look at the top of his head” in a funny way.

Tiktok users apparently just stripped his words out and just loop his laugh. I can’t confirm tho, I’ve never used tiktok and if I see that stupid fucking moving logo on a video I close it immediately