The 'I've Only Had Arlo For A Day And A Half' meme originates from the hit sitcom Brooklyn Nine-Nine, specifically the episode '9 Days.' In this scene, the notoriously tough and stoic detective Rosa Diaz reveals her unexpected soft spot for her new puppy, Arlo, declaring her readiness to commit extreme acts of violence if any harm should come to him. Since its airing, the meme has become the internet's universal shorthand for the intense, immediate bond people form with something new, ranging from actual pets to fictional characters or even software updates. It perfectly captures the 'hyperfixation' culture, where users humorously exaggerate their loyalty to a newfound interest.