@ Normal Gem
EVs: 252 Atk / 4 SDef / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Stealth Rock
- Magic Coat / Zen Headbutt
I originally was using an Azelf on my Hyper Offensive team, however I saw Ojama using this set (or something similar), and I really like it. Mew has several advantages over Azelf, mainly its ability to run a Normal Gem for a more powerful Explosion due to its bulk. With the given EV's, Mew always survives a +1 U-Turn and +0 Bug Buzz from Genesect and it can set-up Rocks. Magic Coat allows Mew to beat opposing Magic Coat Deoxys-D's 1v1 which other Taunt users cannot say, and it prevents faster leads like Terrakion, Infernape, Azelf, and Aerodactyl from setting up on you, as they will Taunt and you will Magic Coat. Explosion provides a self-spinblock, since slower spinners are going to lose not be able to rapid spin if you explode, since the move has nothing to hit. 4 SDef EV's make sure Genesect gets +1 Atk since it can tank a +1 U-Turn but not a +1 Bug Buzz. I'm really impressed by this set-- the only thing I miss is the ability to tank a Specs Draco Meteor or something Turn 1 due to the lack of a Sash that Azelf has, but honestly the power of Explosion makes up for it, e.g. almost always OHKO'ing Xatu. Common etiquette is to Explode turn 1 if your opponent has a Starmie or Magic Bounce. Zen Headbutt can be used if you're scared of Gengar setting up on you, or if you want to hit Tentacruel or fighters trying to set up on you. Tentacruel can bypass the KABOOM with Protect given proper prediction on your opponent's side.
EDIT: This set is really good for HO Teams not wanting to waste a team slot on a ghost-type since this can prevent spins.