Ferrothorn

Ferrothorn finds its role in Doubles as a hard-to-take-down pivot that can take strong resisted moves and recover the lost HP thanks to Leech Seed. Ferrothorn is able to check many common threats in the metagame such as the Island Guardians, Tyranitar, and rain teams in general. Ferrothorn is also handy against bulky offensive teams, as it absorbs most hits they dish out. Ferrothorn has some offensive presence as well, thanks to a decent base 94 Attack stat and a typing that lets it hit common threats like Tapu Fini, Kyurem-B, Tyranitar, and Tapu Lele super effectively. However, its typing makes it 4x weak to Fire, rendering it almost deadweight when an opposing Fire-type Pokemon is out on field. Additionally, Kartana's presence in the tier both operates as a hardstop to Ferrothorn and one that takes up a large part of its niche, not suffering from any of its passivity issues. Ferrothorn's base 20 Speed makes it one of the slowest Pokemon in the tier, which has drawbacks such as draining momentum but also brings good aspects with high Gyro Ball Base Power and high Speed under Trick Room.