Dewgong

Dewgong has never been a common sight in the UU metagame. It's severely outclassed by its cousin Walrein, in terms of both overall stats and ability. Dewgong's defensive stats should by no means be dismissed, however, and its unique ability, Hydration, distinguishes it from its Water- and Ice-type brethren. Dewgong's part Ice typing is quite a mixed blessing. STAB Ice-type moves are always welcome on any team, hitting many common Pokemon super effectively. Defensively, however, Dewgong's Ice typing does it no favors. Stealth Rock hinders Dewgong's ability to tank, as taking 25% damage each time it switches in will wear it down very quickly. Even with these drawbacks taken into consideration, Dewgong can still act as a decent tank in UU play, with handy resistances to the omnipresent Ice- and Water-type attacks.