Terrakion

Terrakion's Speed, power, and coverage are very effective in Doubles. With STAB Rock-type attacks and Close Combat, it is able to maintain offensive pressure against most of the metagame, including common threats such as Mega Charizard Y, Mega Kangaskhan, and Tyranitar. However, Intimidate and burns are very common in Doubles, so until those users are gone, Terrakion won't do much damage unless it lands a super effective hit. In addition, Terrakion's great offensive typing is terrible defensively, leaving it vulnerable to many common attackers, such as Scizor, Latios, and Azumarill. Many strong attacks can KO Terrakion, so one bad prediction can waste Terrakion's teamslot.