Mammochon

Diamond +3: Its impressive tusks are made of ice. The population thinned when it turned warm after the ice age.

Platinum +2: A frozen one was dug up from soil dating back 10,000 years. It woke up to much amazement.

HeartGold: A frozen MAMOSWINE was dug from ice dating back 10,000 years. This Pokémon has been around a long, long, long time.

SoulSilver: It flourished worldwide during the ice age but its population declined when the masses of ice began to dwindle.

Black 2 / White 2: When the temperature rose at the end of the ice age, most Mamoswine disappeared.

X / Omega Ruby: A frozen Mamoswine was dug from ice dating back 10,000 years. This Pokémon has been around a long, long, long time.

Sword: This Pokémon can be spotted in wall paintings from as far back as 10,000 years ago. For a while, it was thought to have gone extinct.

Shield: It looks strong, and that’s exactly what it is. As the weather grows colder, its ice tusks grow longer, thicker, and more impressive.

Legends: Arceus: This species reached its zenith during the period known as the ice age. I suspect that Hisui's frigid climate is in harmony with Mamoswine's constitution, thus awakening hidden potential.