Venusaur

Venusaur is a phenomenal sun sweeper in UU. Venusaur's defensive typing lets it set up on many common Pokemon like Tangrowth, Swampert, and Rotom-W, allowing it to clean teams with its Growth boots. With moves like Giga Drain for reliable recovery, a powerful 100-Base Power and sun-boosted Weather Ball, and Sludge Bomb or Earth Power, Venusaur is able to punch holes in many teams, as with a boost it 2HKOes nearly every Pokemon in the tier barring Chansey. With a Modest nature, it outspeeds every relevant Pokemon in the tier under sun. However, Venusaur is severely limited if sun is no longer active, being outsped and KOed by plenty of Pokemon like Salamence and Azelf or used as setup bait for Pokemon like Scizor. Without a boost, Venusaur can sometimes be too weak to sweep, as common Pokemon like Rotom-H and Moltres are able to survive an unboosted hit and OHKO it back. Lastly, priority users such as Zygarde-10%, Scizor, and Mamoswine can pick off a weakened Venusaur. The inconsistency of sun teams because of Hippowdon limits the prominence of Venusaur in the metagame.