According to the studio, Articuno can still be found in raids until Monday, July 31st, which means that aspiring Pokemon Masters still have some time to add it to their arsenal in Pokemon GO. After that date, however, Moltres will be the raid-based opponent from July 31st to August 8th. Zapdos will then be making his electrifying appearance August 8th and will disappear on August 14th.

Lugia, on the other hand, doesn’t have an expiration date attached to its appearances so it may be sticking around for the entirety of the legendary raid opportunities, which would ensure that the toughest battle in Pokemon GO to-date would remain so for the time being. Lugia also adds a nice bit of variety for those that have been running around battling these powerful beasts – crossing their fingers whenever they’re provided with an opportunity to possibly capture them. Of course, that latter part is easier said than done.

There are currently no plans announced for what will happen after Zapdos wraps up his time in the game, but Niantic has teased several possibilities for which Pocket Monsters may pop up next. Ho-Oh would be a likely candidate, as would the three legendary dogs, but Mewtwo is another Pokemon the studio teased at the end of a recent trailer.

For now, though, players are best to ensure that they take this time to add Articuno to their Pokedex before it disappears indefinitely.

Pokemon GO is currently available on iOS and Android devices.