Obvious troll is obvious
Saying this is like throwing a tantrum because someone is being a total pain. It’s used when you know someone’s just trying to bother you.
You: Why are you arguing with everyone? Them: Obvious troll is obvious.
In a forum thread: This person is impossible. Someone: Obvious troll is obvious.
In a group chat: That guy’s a real pain. You: Obvious troll is obvious.