During the first conversation with Mordok and Fuzmik, Mordok explains to the Sporeling that Babbit keeps stealing their fruits, and Fuzmik tells that he is a pig. Mordok then asks to teach him a lesson, and make him overweight. To the end of conversation, "The mean mean Babbit" quest will be added to the quest log.
The goal is to make him overweight enough to be stuck in the hole. Feed the Babbit at least 3 fruits from tree and he'll go into his hole and be stuck. After he got stuck, the Sporeling can report back to Mordok or Fuzmik to complete the "The mean mean Babbit" quest. However, he can be also rescued by kicking him out of the hole. If he got kicked about 2 times, he will give and drop Suwapootoo fruit to the Sporeling, which will make it exhaust, and then teleport back to the nest. If he got kicked about 3 times, he will provoke to fight with Sporeling.