Defeat the Elite Four 100 times with a team of only Mewtwo and Magikarps, no visiting the Pokemon Center between runs. Then fly to Cinnabar Island and walk around the island 51 times, COUNTERCLOCKWISE, then fly to Pallet Town and talk to Professor Oak who will battle you. Win the batt and he'll give you Mew.

It's funny a few months back when Pokopia was first released I was trying to lookup some information about how to find a certain Pokemon. I stumbled onto some terrible LLM generated page that started off "ok", but quickly went into full hallucination mode. It felt like the good ole days of Pokemon lies on the Internet. I just wish it has been a person lying.