Deoxys in Pokemon Go is the Legendary Pokemon that took the place of Mewtwo for EX Raid Battles.
For a long time, Pokemon Go players could only catch Mewtwo in the EX Raid Battles, but Niantic changed things up in September of last year.
How to Catch Deoxys in Pokemon Go
First off, you need to receive an EX Raid Battle Pass which is only given at random by the game when players defeat Tier-5 raid battles at known Gym Locations. The rule of thumb is if the Pokemon Gym has the word "park" in the name, it's an EX Raid Location. However, that's not always the case, but most players know their region by now and which gyms will offer the raid. The best way to get on is to plan a long raid day and hit all Tier-5 raids at known locations and hope that you receive an EX-pass.
How to Defeat Deoxys in Pokemon Go
Deoxys has four forms, his normal form, speed form, defense form, and attack. They weaknesses are the same for all four, but the attack is the best one to catch as it's an attack-oriented meta.
Deoxys is a Physic type of Pokemon, so it's weak to Ghost, Dark, and Bug, but Dragon is strong against almost everything and has a strong attack.
The best Pokemon to use is Tyranitar with double Dark moves, Deoxys Attack-Form with Poison Jab and Dark Pulse, Gengar with duel Ghost moves, and Honchkrow with double Dark moves. Most players have multiple of every kind, so these Pokemon should do.
Once you defeat Deoxys, you'll have a chance to catch them with a limited amount of Pokeballs. Best of luck and don't rush it!
Photo courtesy of Niantic