Axew

Black +2: They use their tusks to crush the berries they eat. Repeated regrowth makes their tusks strong and sharp.

White +2: They mark their territory by leaving gashes in trees with their tusks. If a tusk breaks, a new one grows in quickly.

Black 2 / White 2: Its large tusks have a tendency to break, but each time they grow back, they grow in harder and sturdier.

Sword: These Pokémon nest in the ground and use their tusks to crush hard berries. Crushing berries is also how they test each other’s strength.

Shield: They play with each other by knocking their large tusks together. Their tusks break sometimes, but they grow back so quickly that it isn’t a concern.