The four Mega Stones were previously unavailable in the games and allow Pidgeot, Heracross, Steelix, and Houndoom to Mega Evolve during battle. To receive the items, select the Mystery Gift option from the menu screen and choose to receive your gift with a code. Input the password “AZUL,” and you can pick up the four Mega Stones from the deliveryman inside any of the games’ Pokemon Centers.
First introduced in Pokemon X and Y, Mega Evolution allows certain Pokemon to transform during battle after being equipped with the proper Mega Stone. Mega Evolved Pokemon gain a number of dramatic enhancements over their base forms, from increased stats, new abilities, and occasionally different elemental typing. The series’ most recent installments, Sun and Moon, largely replaced Mega Evolution with Z-Moves, though players could still acquire certain Mega Stones within the games after clearing the main story. Not every Mega Stone can be obtained in the titles, however, so Nintendo has been distributing the remaining ones at events and through the Mystery Gift feature.
Sun and Moon players also have a chance to add a special Midnight Form Lycanroc to their teams. Beginning May 15, GameStop stores around the US are distributing a serial code for the Pokemon. As with this batch of Mega Stones, players need to enter the code in the games’ Mystery Gift option to receive their Lycanroc. UK players, meanwhile, can pick up a code for Lycanroc at GAME stores.