Professor Burnet and her Munchlax appeared in a TV spot for the former's award for the "Lady of the Year in Alola". The two met up with Professor Kukui's class at the Aether Foundation when they were diving in the water. As the class visited Kukui's house, Munchlax watched the TV with the group, and was amazed to see Oluolu with his Snorlax playing PokéBase. As others prepared the meal, Munchlax dashed out and ate the food before anyone could touch it. Afterwards, it fell asleep. Burnet and Munchlax went to Altar of the Sunne on Poni Island. They faced groups of Jangmo-o and Hakamo-o, but were helped out by Professor Kukui and his Braviary. Munchlax waited while Burnet and Kukui set up the equipment for researching Ultra Wormholes.
Munchlax was helping Ash and his Pokémon clean the dishes while Kukui and Burnet were absent. On the day Burnet and Kukui were getting married, the two sent their Pokémon out as their partners, to walk them to the altar. Once Samson declared the two as husband and wife and let them kiss, Munchlax immediately smooched Samson himself. The following day, Munchlax helped Burnet in researching a Pyukumuku underwater, until Ash told them breakfast was ready. Just as the breakfast began, Munchlax immediately ate the Pokémon food, as Rotom noted it ate 10 times the normal portion of food in just three seconds. Burnet wanted to give Team Rocket's Mareanie, whom she, Kukui and Ash found on the beach, some food to cheer her up, but Mareanie refused to eat. Her Munchlax attempted to eat the food, but Burnet reminded that was not polite.
Munchlax accompanied Professor Burnet, Kukui and Ash in shopping, when they encountered Mina and her paintings, in which Ash's Poipole was interested in. Munchlax, Burnet and Kukui meditated on their surf boards, when Ash joined them. Burnet and Kukui reminded the importance of respecting the nature and the Pokémon, which were the spirit of Alola. It also attended the fireworks festival with Burnet, Kukui, Ash and his classmates, as well as his friends from Kanto: Brock and Misty. Ash and Pikachu joined Lillie to go to Aether Foundation to give Burnet and her Munchlax the lunches they forgot. Munchlax was eager to eat the food, but Pikachu prevented it from eating too early.
Professor Burnet and her Munchlax, along with Lusamine, Wicke and Faba were watching Ash's battle against Hau, during the Alola Pokémon League. Munchlax accompanied Burnet during breakfast with Ash and Kukui, after the Pokémon League was over.
None of Munchlax's moves are known.
- ^ SM044: A Dream Encounter!
- ^ SM046: Deceiving Appearances!
- ^ SM048: Night of a Thousand Poses!
- ^ SM052: Revealing the Stuff of Legend!
- ^ SM053: Rescuing the Unwilling!
- ^ SM055: The Professors' New Adventure!
- ^ SM056: Let Sleeping Pokémon Lie!
- ^ SM058: Fighting Back the Tears!
- ^ SM084: The Shape of Love to Come!
- ^ SM100: Battling the Beast Within!
- ^ SM103: Heart of Fire! Heart of Stone!
- ^ SM096: Don't Ignore the Small Stufful!
- ^ SM133: Battling on the Wing!
- ^ SM145: Dreams of the Sun and Moon!