Mega Metagross is very good at being fast, offensive, and bulky all at the same time. Its go-to move, Heavy Slam, will deal huge damage because it turns out that Metagross is quite heavy compared to the rest of the field. Heavy Slam also gets boosted further by Tough Claws, making it deal great damage even on neutral hits. With Metagross, Heavy Slam is the move you want to click most. Psychic Fangs is the best Psychic move Metagross gets, and it has a decent array of coverage it can utilize for the third move. Metagross works well on rain based teams, since Water types will handle the Fire and Ground types Metagross dislikes. Pairing Metagross with a way to boost it even further, via Tailwind or Coaching, can allow it to take over games. Metagross can be played bulky or fast, allowing you to be more creative with the EV spread, but being min-maxed is still an acceptable option.