Rillaboom

Rillaboom is among the best pivots in the metagame thanks to its excellent ability, useful utility moves, and strong priority STAB attack. Grassy Surge lets Rillaboom set Grassy Terrain on switch-in, providing passive healing for teammates and slowing down threats that benefit from Psychic Terrain such as Necrozma. Grassy Glide is given priority and boosted by Grassy Terrain, letting Rillaboom soft check a wide variety of threats regardless of Speed, such as boosted Dragon Dance Zygarde and Diancie under Trick Room, as well as picking off any Pokemon low on health. Rillaboom works well on a variety of team archetypes thanks to the sheer utility it provides. For example, structures that rely on Trick Room or setup appreciate Rillaboom’s ability to create safe turns through the use of Fake Out, while the latter also appreciates Grassy Terrain's passive healing to keep wincons healthy. Volcanion and Urshifu-R synergize well with Rillaboom, as they remove Fire-types and Kyurem-B, respectively, and in return, Rillaboom checks Water-types such as Tapu Fini. Rillaboom is not without faults, though; its Grass typing leaves it with a plethora of weaknesses that are exposed by common Pokemon such as Kyurem-B and Genesect, and it can be tricky to use alongside other Terrain setters. It's also worn down quickly by pivoting in and out, especially with entry hazards up, as it typically has no recovery besides Grassy Terrain and doesn't carry Protect, leaving it open to being attacked every turn and susceptible to double targets.