Mega Metagross uses the Tough Claws Ability which increases the Attack power of moves that require physical contact against the opposing Pokémon.
Metagross can Mega Evolve into Mega Metagross if it is holding a Metagrossite.
Mega Metagross resides in the Overused (OU) tier of competitive battling. With a great ability in Tough Claws and a strong 145 base Attack, Mega Metagross is a physical force in the tier. Coupled with a great 110 base Speed and good 80/150/110 bulk, Mega Metagross can have numerous switch-in opportunities and put heavy pressure on opposing teams as a result. Its best sets are its all-out attacking set that has good coverage options to handle the majority of the Pokémon in the tier and its Rock Polish set that gives Mega Metagross a nice Speed boost and a means to sweep. The flaws in Mega Metagross are its lackluster Speed prior to Mega evolving and its susceptibility to status which can be troubling when trying to check some Pokémon, such as Will-O-Wisp Mega Gardevoir or Thunder Wave Clefable. Despite this, Mega Metagross is a threat not to be underestimated and a phenomenal Mega evolution.
Related ThreadsTons of New Mega Metagross details! - last post @ Jul 14, 2014
Latest Megas: Mega Lopunny, Mega Altaria and Mega Salamence (CoroCoro) - last post by @ Aug 10, 2014
Mega Metagross confirmed! - last post by @ Jul 10, 2014
New Gameplay Trailer! Mega Metagross, Pikachu Cosplay, Gym Leaders, and More! - last post by @ Jul 25, 2014
Pokemon Omega Ruby, Alpha Sapphire are Mega Evolving this Steel/Psychic, meet Mega Metagross - last post @ Jul 13, 2014