Dorian asks you to give him a Buizel that is a different size from the one that he has.

The Request

Talk to Dorian outside of the southern gate of Jubilife Village to accept the request.

Catch Buizel

Buizel can be found in Obsidian Fieldlands, in the Horseshoe Plains and Windswept Run areas. Catch one and give it to Dorian, and if it is at least 2'8", he will take it. You can check a pokémon's height by opening your Satchel or visiting the Pasture and viewing the pokémon's summary.

Reward

After you give Dorian a Buizel that is 2'8" or bigger, you will get 5 Oran Berries and 1 Exp. Candy S.