Place it right after the absurd claim in an edit, letting it serve as the verdict before cutting to the reaction shot. Pair it with the Bruh Meme Sound for a slower second dismissal, or follow it with the Fail Sound Meme when the argument collapses completely.
About this sound
This under-four-second clip is a loud, exasperated line from Step Brothers, with the voice rising sharply on insane as one stepbrother bluntly dismisses the other. It feels abruptly incredulous and funny, turning a wild claim into something absurd in an instant. It comes from the 2008 comedy starring Will Ferrell and John C. Reilly as Brennan Huff and Dale Doback, whose constant bickering drives the exchange.