Quagsire has three abilities available to it, Damp, Water Absorb, and the Dream World ability Unaware. The first ability, Damp, prevents all Pokemon currently in the battle from using the moves Explosion or Selfdestruct. The second ability, Water Absorb, gives Quagsire an immunity to Water-type attacks. If it should be hit by a water attack, it will recover the damage that it would've normally taken. However, it is only possible to recover up to 25% of max HP in this way. The DW ability available to Quagsire, Unaware, ignores the opponent's boosts in all stats other than Speed while Quagsire is in the battle. However, the move Punishment still factors in these boosts.
Wooper may evolve into Quagsire beginning at level 20.
Quagsire resides in the Neverused (NU) tier of competitive battling. Thanks to its ability Unaware and a good defensive typing that leaves it with only one weakness, Quagsire is a great defensive Pokémon that can check the majority of set-up sweepers in the tier. With access to Recover, Quagsire can keep itself relatively healthy to consistently check certain physical set-up sweepers such as Klinklang and Scyther. However, it does suffer from being very susceptible to Grass-type Pokémon like Sceptile, Ludicolo, and Lilligant. Its only passable physical bulk means that it can not handle some of the stronger physical attacks in the tier such as Zangoose's boosted Facade. It also struggles to fit in on any other team archetype other than defensive teams.
Quagsire is viable in the Rarelyused (RU) tier of competitive battling. With an ability to check some of the tier's most threatening sweepers like Swords Dance Drapion thanks to its ability Unaware, Quagsire is able to carve itself a nice defensive niche in the tier. Quagsire does suffer from its lackluster Special Defense stat and vulnerability to Taunt due to its generally passive nature. It also often gives the Grass-types of the tier a free switch-in, and it faces immense competition from other bulky Water-types like Alomomola, Slowking, Seismitoad, and Jellicent.
Quagsire has a small niche in the Underused (UU) tier of competitive battling as the only viable Pokémon having the ability Unaware which allows it to check certain threats like Mega Aerodactyl and Feraligatr. Quagsire also has access to a reliable recovery move in Recover and a solid defensive typing, but its overall bulk is only decent at best which means that it can be overpowered by strong physical attacks. It is also faced with heavy competition from other bulky Water-types like Suicune, Milotic, Alomomola, and Empoleon, all of which have better overall bulk and can provide certain niches that Quagsire lacks entirely.
Quagsire is also viable in the Overused (OU) tier of competitive battling. With a great defensive typing and Unaware to handle some of the tier's most imposing physical sweepers such as Belly Drum Azumarill, Mega Charizard X, Mega Scizor, Quagsire finds itself on stall teams very frequently due to this extremely valuable niche. It can provide a great stop to Electric-types that try to gain momentum for their team like Raikou and Mega Manectric while having Scald and Recover to outstall a great number of physical threats in the tier. However, Quagsire does have an exploitable weakness in Grass which can be problematic with Pokémon like Mega Metagross that can run Grass Knot. Quagsire also suffers from having underwhelming stats all across the board, with physical bulk that cannot handle some extremely powerful threats while its special bulk is severely lacking. It also faces competition as an Unaware user from Clefable, which has better special bulk and can bring overall better utility for the team, although Quagsire can check physical set-up sweepers much better.
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