Three new Shiny Shadow Pokémon are available in Pokémon GO. Here's how you can obtain all three.
The three new Shiny Shadow Pokémon are Growlithe, which can be obtained by defeating Arlo; Omanyte, which can be caught once you beat Cliff; and Drowsee, which can now be encountered after a battle with Sierra. This replaces the previous wave of Shiny-capable Shadow Pokémon from the leaders of Pineco, Grimer, and Lapras. Many trainers who struggled with the tankiness of Sierra's Lapras will be happy to see that powerhouse replaced by Drowsee, but don't discount this new team. These battles are definitely worth preparing for because these Shadows will hit quite hard. This week, Bleeding Cool will debut in-depth battle guides to help trainers defeat Arlo, Cliff, and Sierra with these news teams and hopefully catch Shiny Shadow Pokémon.
Currently, since the exit of Jessie and James, Shiny Shadow Pokémon are only available through the Team GO Rocket leaders… with one exception. Currently, there is a Psychic-type Team GO Rocket grunt that can still lead to Drowsee encounters. This was similar to a situation that happened during the beginning of the previous Rocket cycle when the "Winning is for winners" Grunt could briefly lead to encounters with Shiny Shadow Lapras. That Grunt was quickly disabled in the game to make it so the Lapras was only obtainable through Sierra, and that will likely happen in this situation as well.
Before we get into the raid guides this week, a major tip for Team GO Rocket Leader battles is that the first thing you want to do is take down shields. Taking down their shields is the top priority over inflicting the most damage, so you always want to make sure that you use Pokémon with Charged Attacks that power up very quickly.