February 27 is Pokemon Day, the anniversary of Pokemon Red and Green's release in Japan, and Pokemon Go is commemorating the occasion with a special in-game event. This year's Pokemon Day celebration runs from February 25 to March 2, and it brings back a special Legendary and introduces new kinds of Pokemon to the game.

To coincide with the Netflix release of the latest Pokemon movie, Mewtwo Strikes Back: Evolution, Armored Mewtwo will return to five-star Raid Battles during this year's Pokemon Day event. This time, the Legendary will know the Psychic-type Charged attack Psystrike.

In another tie-in with the movie, Clone Pokemon will make their debut in Go, marking the first time these monsters have ever appeared in a Pokemon video game. You'll be able to encounter Clone versions of Venusaur, Charizard, Blastoise, and other Pokemon in four-star Raids, while Clone Pikachu may photobomb Go Snapshots you take during the event.

Additionally, a variety of festive Pokemon will be available throughout the event. Party hat-wearing versions of Pikachu and Eevee will appear in the wild, while party hat Bulbasaur, Charmander, and Squirtle may hatch from 7 km eggs. Not only that, but there's a chance you may find Shiny versions of these Pokemon.

Finally, before the Pokemon Day celebration ends, Niantic will host a special Raid Day on March 1 from 2-5 PM local time. During the event, party hat-wearing versions of Nidorino and Gengar--the two Pokemon that famously squared off in Pokemon Red and Green's opening movie--will appear in Raids, and these will likewise have a chance of being Shiny. You can read more about the Pokemon Day celebration on the official Pokemon Go website.

Niantic has a ton of other events lined up for Pokemon Go this month, including February's Community Day, which will feature Rhyhorn. A new Legendary Pokemon, Tornadus, has also begun appearing in Raids, and there's a new batch of Field Research tasks to complete in the game.