Mamoswine's debut was in Hungry for the Good Life! as a stray and hungry Swinub. It appeared at Mr. Backlot's mansion from a nearby forest and always came over for something to eat. It caused trouble by devouring all of Dawn's Poffins showing a liking to them, but caused much displeasure to Dawn's other Pokémon. However, after helping take down Team Rocket and rescue the other Pokémon, Dawn decided she wanted Swinub to go with her. It had a very cheerful, happy personality and would often jump up and down in excitement.
While still a Swinub, it was not used very much due to its relative lack of battling and Contest experience. In Battling The Generation Gap!, Swinub watched its first Contest when it saw Dawn, Buneary and Ambipom work together to win the Celestic Town Contest. Swinub evolved into Piloswine in Sleepless In Pre-Battle! in a battle against Team Rocket. After evolving Piloswine was initially still very affectionate towards Dawn, as seen in Get Your Rotom Running! where it tackled her to the ground out of affection. This affection would be short lived, however.
Its personality drastically changed in A Breed Stampede!. Just two episodes after evolving, Piloswine started to develop an indifference towards Dawn and became prone to disobedience. Knowing numerous powerful attacks, Piloswine felt much stronger and more confident than it did as a Swinub. It felt that it wasn't weak and was very powerful. On numerous occasions it tried to attack Dawn or her Pokémon. It attacked Piplup for touching its fur presumptuously, and tried to attack Dawn with Ice Shard, instead freezing half the body of Grotle who tried to stop it from rampaging. Dawn agreed to have a battle with her Piloswine and Grotle. However, it ignored Dawn's commands and used Ancient Power instead. It later evolved again into Mamoswine after being attacked by Team Rocket. Unfortunately, it has kept its bad behavior from when it was a Piloswine. Despite this, Dawn is still eager to train Mamoswine well.
In Trials and Adulations!, Mamoswine was injured during a battle against a wild Aggron. Dawn and her Pokémon used the first aid skills taught to her by Brock in Doc Brock! to help Mamoswine recover, and later attempted to protect Mamoswine against Team Rocket. As a result, Mamoswine gained respect for Dawn and under her instructions, it was able to defeat Aggron. From then on, Mamoswine still has a tiny bit of a rebellious attitude, but when Dawn is in danger it does not hesitate to help her.
In Old Rivals, New Tricks, although it pretended not to be interested, Mamoswine helped Ambipom train for the upcoming Pokémon Ping Pong Tournament. Later during the Contest it tried to sleep instead of cheerleading, as usual. Although when Ambipom started battling Kenny's Prinplup, it started to watch and eventually got completely drawn into the excitement with wide eyes.
In Promoting Healthy Tangrowth!, Dawn decided to train the Twin Tusk Pokémon for her upcoming Contest. All was going well until Mamoswine causes an accident and runs off into a jungle, angry and embarrassed, causing Dawn to go after it. A wild Tangrowth appears and attacks Mamoswine, defeating it with Absorb. Team Rocket later appears to cause havoc, and Mamoswine successfully learns Hidden Power in the process of attacking Team Rocket.
In Dressed for Jess Success!, Dawn used Mamoswine in its first Contest during the Battle Round of the Lilypad Contest. Earlier in the episode, Dawn taught it a trick that utilizes swallowing Ice Shard to create ice spikes on its back, inspired by Ash's Grotle swallowing its own Energy Ball. Unfortunately however, during their battle against Carnivine, it lost its temper and began rampaging out of control, resulting in a loss. However, despite Mamoswine being saddened by the loss, it was eager to begin training again.
In Double-Time Battle Training!, Mamoswine was training to find its Contest partner. It failed to sync with both Piplup and Pachirisu. It finally found its partner after it worked well with Cyndaquil after a successful Flame-Ice. Though the new partners were defeated during their practice battle against Zoey, after Zoey's Kirlia used Psychic to control her Leafeon's Magical Leaf.
In Playing the Performance Encore!, Mamoswine and Cyndaquil were used for the battle round of the Daybreak Contest. The Flame-Ice combination was used by Dawn in the battle against her first foe's Houndoom and Mightyena, but it failed due to the ice melting. In the battle with Ursula, Dawn started using both of Mamoswine and Cyndaquil's capabilities. Mamoswine swallowed Ice Shard which made the fur on Mamoswine's back and head freeze into large spears of ice which cause extra damage when Take Down is used. It was also used in the two-on-two Contest Battle against Ursula's Minun and Plusle when Cyndaquil used Swift to surround Mamoswine. Cyndaquil then turned the flame on its back on as the two charged for Ursula's Plusle and Minun. Despite Ursula losing some points, the move failed to hit the two Pokémon. After managing to work together to both attack and defend against Ursula's Pokémon's attacks, as well as mastering the Flame-Ice combo, Dawn managed to win the battle, earning her fifth Ribbon.
In Opposites Interact!, Mamoswine was used alongside Pachirisu in the first battle round of the Grand Festival against Gabite and Flareon. Despite a good start, Mamoswine and Pachirisu soon found themselves struggling and Mamoswine found itself overpowered by Flareon's Fire-type moves as well as a powerful Scary Face and Shadow Ball. However Pachirisu and Mamoswine were able to pull off Dawn's newest improvised move, Ice Chandelier, despite Pachirisu having originally practiced with Buneary. As a result, both Gabite and Flareon were defeated.
Mamoswine made another appearance in Familiarity Breeds Strategy!, where it was briefly seen helping Ash's Gliscor train its Giga Impact.
Mamoswine appeared again in SS024 to help fight off the Ariados that were attacking Dawn. Mamoswine was caught in String Shot and helpless until Quilava saved it.
In Piplup, Pansage, and a Meeting of the Times!, Mamoswine was introduced to Ash, Iris and Cilan's Pokémon. It was disturbed by an invisible Meloetta and began sniffing around for it. Later, in The Mystery of the Missing Cubchoo!, Mamoswine battled Ash's Pignite. The battle ended in a draw when both Pokémon were knocked out by a collision of their attacks.
It was used by Dawn in Battling Authority Once Again! during the second round of Pokémon World Tournament Junior Cup. Mamoswine went up against Iris's Dragonite and hit its opponent with numerous Ice Shard attacks while Dragonite refused to dodge as he was disobeying his Trainer. Mamoswine attempted a Take Down on its opponent, but was thrown across the battlefield by its tusks. Mamoswine got straight back up and landed a direct hit on Dragonite with a second Take Down. It was then revealed Mamoswine had learned Ice Fang when Dawn called for it as a finishing move. Dragonite began to freeze as he held Mamoswine's frozen tusks back. However, he escaped upwards and launched a Dragon Rush attack. Mamoswine was defeated by the massive hit.
Personality and characteristics
Much like Munchlax did with May, Swinub decided to follow Dawn for her cooking abilities. As a Swinub in its debut it showed to be quite lazy and gluttonous and Dawn quickly realized it was too early for battles and decided to put its contest debut on the hold.
However, some episodes later it began to change due to its new power and newfound confidence, similar to the fate of Ash's Charizard. This became a problem, as it decided to ignore all of Dawn's commands. The situation became even worse after evolving again into Mamoswine, now having inherited a quite violent and rude personality, attacking Dawn and her Pokémon several times.
Even after it began to obey Dawn, it still showed to be an out-of-control Pokémon, as seen in its contest debut where it showed a catastrophic result due to its short fuse. After Dawn began training for Double Performances, it froze several of Dawn's Pokémon in trying to partner up for an appeal, albeit all were unintentional, until it found its perfect partner: Cyndaquil. After that Mamoswine showed to have returned to its friendly personality, thus becoming a more serious Pokémon.
In battle, Mamoswine has shown to be incredibly powerful thanks to its large and powerful physique. It was shown to take Piplup's Bubble Beam, Whirlpool and Peck in quick succession with no resistance at all as well as knocking him out for the third time in A Breed Stampede!.
Mamoswine wasn't interested to watch Dawn compete in Pokémon Contests initially; instead, it just slept with a pompom on its head. Later on, during Dawn's battle with Ursula in Another One Gabites the Dust!, Mamoswine sparked an interest after seeing Dawn and Pachirisu use Pachirisu's new move to the fullest.
In the manga
- Sleepless In Pre-Battle, the episode in which Swinub evolves into Piloswine, first aired in Japan in the same week that Hungry For the Good Life!, the episode in which Swinub is captured, first aired in the United States. The same thing happened to Ash's Gliscor and Gligar.
- Both of Mamoswine's evolutions happened during a battle with Team Rocket.
- Mamoswine is the second of Dawn's Pokémon to evolve by the method of knowing a certain move, the first being her Ambipom.