Volcarona

Volcarona boasts a great base 135 Special Attack stat and access to a great spread STAB move in Heat Wave. With the right investment and nature, it can Speed tie with Mega Kangaskhan and other threatening base 100 Speed Pokemon. Volcarona also has access to Flame Body, which can burn physical attackers, and Swarm, which can boost its already powerful Bug Buzz. It also has access to both Rage Powder and Quiver Dance. However, Volcarona has a massive 4x weakness to Rock, which is one of the most common attacking types in Battle Spot Doubles, as well as painful weaknesses to Water and Flying. One last negative factor about Volcarona is that it can't really do much outside of its STAB attacks and support moves.