In Pokémon Pokopia, what title does Tangrowth receive after meeting Ditto?

In Pokémon Pokopia, Tangrowth receives the title Professor Tangrowth after meeting Ditto.

Professor Tangrowth is the only resident Ditto initially encounters in the Withered Wasteland. The world has withered, and humans and most other Pokémon have disappeared. Tangrowth lives alone there and helps explain the mysterious state of the setting.

After Ditto discovers a Pokédex among items found by Tangrowth, the two begin restoring Pokémon habitats. Their work attracts more Pokémon to the wasteland, and those arrivals help Ditto complete tasks and learn useful moves. Professor Tangrowth also hopes that the return of Pokémon will eventually encourage humans to come back.

The name is a character title rather than a separate species. Tangrowth remains a Tangrowth, while “Professor” identifies its role as a guide and knowledgeable companion. This is similar to other named characters in the game, such as Chef Dente, DJ Rotom, Mosslax, Peakychu, and Tinkmaster.