Darkrai

Boasting a blazing-fast base 125 Speed and a stellar base 135 Special Attack, Darkrai is one of the most potent sweepers present in Ubers. With access to Nasty Plot and a fantastic Dark STAB, this malevolent specter of darkness has quite a few tricks up its sleeve, more than enough to make its enemies shudder in fear. Its signature move, Dark Void, a sleep-inducing move with 80% accuracy, allows Darkrai to set up with extreme ease, and makes it very difficult to counter. Darkrai's ability, Bad Dreams, complements this well by causing enemy Pokemon to lose health slowly while they are asleep, breaking their Focus Sashes. In addition, Darkrai is one of the few Pokemon that Wobbuffet cannot touch, as Darkrai is immune to Mirror Coat. Indeed, Darkrai is sometimes known as the bane of stall teams, and for good reason. Darkrai's only true flaw is its average defenses, which allow it to be taken down by powerful neutral attacks.