If held by a Sharpedo, allows it to Mega Evolve into Mega Sharpedo 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 Sharpedo a Sharpedonite or remove a Sharpedonite from Sharpedo.
Outside of battle
If held by a Sharpedo, allows it to Mega Evolve into Mega Sharpedo when it performs a Spectacular Talent during a Pokémon Contest Spectacular while its Trainer has a Key Stone. Sharpedo will remain a Mega Sharpedo until the Talent Round ends.
The player can obtain the Sharpedonite by defeating Mega Sharpedo in Stage 600 found on Prasino Woods.
The Lucarionite was also available as a prize during the Mega Sharpedo Competitive Stage. This Competitive Stage ran on the Nintendo 3DS version from September 7 to 14, 2015; January 25 to February 2, 2016, and November 8 to 15, 2016. It ran on the Pokémon Shuffle Mobile from January 25 to February 2, 2016; and November 8 to 15, 2016.
The Sharpedonite enables the following Mega Evolution:
Adds one more Mega Sharpedo above the match. Actually converts the tiles directly above all other Mega Sharpedo into a Mega Sharpedo. This effect can replace any disruption in the tile above and counts as erasing the content of the tile for damage, but does not affect black-cloud disruptions. Does nothing if the above tile is empty.