The phrase comes from everyday Brazilian Portuguese, where ta aqui is a casual way to say here it is and bicho is flexible slang for a dude, animal or thing. Clips using the line spread through Brazilian WhatsApp groups, meme pages and short video edits, where it became a reusable audio for entrances and reveals. Its appeal is the contrast between the confident announcement and whatever ordinary or ridiculous thing appears next, which keeps it useful far beyond its original context.