If held by an Abomasnow, allows it to Mega Evolve into Mega Abomasnow if its Trainer has a Key Stone. Each Trainer can only Mega Evolve one Pokémon per battle.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot give Abomasnow an Abomasite or remove an Abomasite from Abomasnow.
Outside of battle
If held by an Abomasnow, allows it to Mega Evolve into Mega Abomasnow when it performs a Spectacular Talent during a Pokémon Contest Spectacular while its Trainer has a Key Stone. Abomasnow will remain a Mega Abomasnow until the Talent Round ends.
The player can obtain the Abomasite by defeating Mega Abomasnow in Stage 620 found on Zaffiro Coast.
The Abomasite was also available as a prize during the Mega Abomasnow Competitive Stage. This Competitive Stage ran on the Nintendo 3DS version from February 9 to 16, 2016; May 31 to June 7, 2016 and December 6 to 13, 2016. It ran on the Pokémon Shuffle Mobile from May 31 to June 7, 2016; and December 6 to 13, 2016.
The Abomasite enables the following Mega Evolutions:
An Abomasite appeared in A Real Icebreaker!, worn by Wulfric's Abomasnow. The Frost Tree Pokémon wears its Mega Stone on its chest, revealing it only when it was about to Mega Evolve. Wulfric used it during Ash's rematch against him, in which it battled Greninja.