Pesselle needs your help making a medicine out of Croagunk's poison.
The Request
Check on the blackboard in Professor Laventon's office in Galaxy Hall to accept the request.
Talk to Pesselle
Talk to Pesselle in Galaxy Hall to proceed.
Catch a Croagunk
Croagunk can be found in the Crimson Mirelands, in the Gapejaw Bog area, the Scarlet Bog area, and the Holm of Trials area.
Give Pesselle a Croagunk
Go back to Jubilife Village and enter Galaxy Hall, and talk to Pesselle to hand over a Croagunk.
Reward
You will get 3 Full Heals and 3 Exp. Candy S as a reward.