The line comes from Phineas and Ferb, the Disney Channel animated series that ran from 2007 to 2015. In almost every episode, Phineas greets his pet platypus with some version of 'Oh, there you are, Perry,' usually right after Perry has slipped away on a secret mission as Agent P. The running gag made the phrase one of the show's most quoted moments, and the Spanish-dubbed delivery took on a second life as a meme sound for reveal and caught-you edits. Fans still drop it whenever a character, pet, or friend pops up unexpectedly.