Blastoise

Mega Blastoise is one of the best wallbreakers in the STABmons metagame thanks to its hefty Special Attack stat and very helpful ability in Mega Launcher that boosts Origin Pulse to a 165 Base Power move while also making its coverage options like Dark Pulse and Aura Sphere hit significantly harder. Mega Blastoise's access to Rapid Spin makes it helpful for teams that need entry hazard control. It also has above-average bulk and a good defensive typing, boasting only two weaknesses. However, Mega Blastoise does have its shortcomings, namely its lack of boosting moves and its lack of reliable recovery, which make it unable to break through dedicated special walls and leave it more easily worn down over the course of a game. Mega Blastoise also takes up the team's Mega slot, removing the possibility of running other very powerful and useful Mega Evolutions. Mega Blastoise's subpar Speed also limits its sweeping potential late-game, and, as regular Blastoise is not viable in STABmons, its item choice is restricted to its Mega Stone. Lastly, the Mega slot can be freed up by replacing Mega Blastoise with other powerful Water-types such as Keldeo, which offers a secondary typing, and Starmie, which can do many of the things that Mega Blastoise can and also has access to Rapid Spin.