Tentacruel

Tentacruel's niches in the Ubers metagame include providing entry hazard control with Rapid Spin and access to Toxic Spikes, which is especially good against offensive teams. Tentacruel counters leads such as Deoxys-S, Scolipede, and Greninja, as well as Klefki, Arceus-Water, Lugia, Skarmory, and Aegislash. It also checks Dialga, Ferrothorn, and Mega Gengar. A very important advantage Tentacruel also has is its ability to beat common Magic Bounce users with Scald, which is super effective against Mega Diancie and can cripple Mega Sableye with a burn.

However, Tentacruel is setup bait for dangerous Pokemon such as Mega Salamence and Primal Groudon. Additionally, Tentacruel's mediocre offenses make it easy for Pokemon such as Primal Groudon, Mewtwo, and Ho-Oh to switch in and retaliate with powerful attacks. Finally, Tentacruel faces fierce competition from Arceus-Water and Primal Kyogre, which are both bulkier and stronger offensively but lack Toxic Spikes and Rapid Spin.