The player can obtain the Beedrillite by completing the Competitive Stage available in Week 17 of the event rotation.
The Beedrillite was also available as a prize during the Mega Beedrill Competitive Stage. This Competitive Stage ran on both the Nintendo 3DS and Mobile versions from September 27 to October 4, 2016; August 15 to 22, 2017; December 19 to 26, 2017; and January 30 to February 6, 2018.
The Beedrillite enables the following Mega Evolution:
Erases Pokémon and disruptions around a spot you tap. Erases nine tiles in a square shape surrounding each spot. Does not activate if the foe is defeated. Only gives 3 seconds to tap. Can choose not to erase any. The disruption countdown formerly did not decrease if this effect was triggered by the first match of the combo, but this was corrected in Version 1.3.28 (3DS)/1.9.1 (Mobile).
In PS616, Giovanni was revealed to have obtained a Beedrillite. He used it to Mega Evolve his Beedrill as part of his explanation that the meteoroid threatening to destroy the world may be housing a Pokémon inside of it.