Manectric

While Mega Manectric does possess blazing Speed and good coverage, its only decent Special Attack and frailty let it down, holding it back from being a decent attacker in DOU. Its attacks often lack the needed power to get a finishing punch on most foes, leaving it open to attacks with its paltry bulk if it doesn't get a KO. Its lack of bulk and notable resistances leave it unable to safely switch into attacks and make it prone to getting significantly damaged by any strong blow; if opposing speed control is up, Mega Manectric simply becomes a liability. Its access to Intimidate is quite nifty, however, giving it a way to support its teammates by weakening opposing physical attacks, and its combination of high Speed and super effective coverage makes it decent for late-game clean-up situations. Being an Electric-type is also a boon for a fast attacker, as this means Mega Manectric can't be paralyzed. Despite that, however, Mega Manectric isn't a recommended pick due to costing a Mega Evolution when it's mostly subpar; a different Mega Evolution such as Mega Kangaskhan or Mega Diancie would often yield better results.