The line comes from the 'what the dog doin' meme that exploded on TikTok and meme pages around 2021, built on clips of dogs caught mid-weirdness while a deadpan voice narrates the obvious question. The profanity-spiked 'TF' version quickly became the punchier soundboard staple, the same family as reaction memes like bruh and oh my god bro oh hell nah man. Its staying power is simple: dogs keep doing inexplicable things, and creators always need a two-second way to say so.