Unown Raid Pokémon GO during Enigma Week will be your only chance to encounter a Shiny Unown. Here's everything you need to know to grab these particularly rare Pokémon.
Unown Raid Pokémon GO: How to Catch Unown U, L, T, R, A
Unown will be appearing in two-star Raids, so they won't be difficult to dispatch. There are five varieties this time for you to look out for, so be sure to battle and catch all of them.
Their Shiny Forms will also be boosted during this week. Shiny Unown are totally unavailable outside of events, and they're even more exclusive due to the different forms. You'll definitely want to grind out Shiny Unown for this event, as there's no telling when any of these particular letters will return.
You won't know if they're Shiny until you've defeated them and are in the capture screen. Shiny Unown are blue instead of black.
As for battling them, they're just pure Psychic type Pokémon. Any strong Ghost or Dark type will make quick work of them, especially since they're only two-star Raid bosses. They're just like how they are in the main series games: weak. Their only moves are Hidden Power and Struggle. Each Pokémon using Hidden Power has a hidden type that their attack will be, but Unown is so weak you'll never have to worry about any disadvantages your Pokémon will have.