Tangrowth, known as Professor Tangrowth, first teams up with Ditto in Pokémon Pokopia.
After Ditto discovers an old Pokédex and adopts a human-like form, it meets Tangrowth in the ruined world. Tangrowth has taken on the title Professor Tangrowth and is studying the environment while trying to understand why humans and Pokémon disappeared.
The meeting gives the story a guide and a research-minded companion. Together, Ditto and Professor Tangrowth investigate the damaged landscape and work to restore habitats. Their goal is not simply to build a settlement, but also to uncover the history behind the world's collapse.
Tangrowth is an evolved Grass-type Pokémon whose design suits the game's overgrown, nature-centered setting. The character should not be confused with other plant-associated Pokémon such as Torterra or Roserade: the professor encountered at the beginning is specifically Tangrowth.