Tentacruel

Tentacruel was a bit on the fence last generation in regard to viability in the Uber tier. This generation has been kinder, granting it a few traits that make it quite useful and provide it with longevity. Rain Dish is a great boon, and it doubles Tentacruel's recovery per turn (assuming rain is up, of course). Tentacruel also boasts both Toxic Spikes and Rapid Spin, two much sought-after moves in the Uber tier. The jellyfish also has quite good synergy with both Giratina-O and Ferrothorn, which can both help Tentacruel in various ways. Unfortunately, Tentacruel has rather poor physical bulk, and will fall easily to Earthquake and other physical attacks. Although 12.5% recovery per turn is nothing to laugh at, Tentacruel still lacks the staying power Pokemon such as Ferrothorn have against powerhouses, and the lack of significant recovery will usually catch up to it eventually. However, do not let these disadvantages deter you from thinking Tentacruel can be one annoying little jellyfish.