Originally Posted by Fat yee
I've never seen any Mew like that, but I have seen a bunch with Normal Gem Explosion and Zen Headbutt which seems accepted as the standard. If you're going to run that variant run Low Kick over Aura Sphere so Tran / Tar will take meaningful damage (and watch out for Tentacruel).
The only 100% counter to all Deo-D leads on it's own is Xatu (or some weird Espeon) which should be made a point. Taunters still have to deal with Magic Coat, U-Turners with Tanga Berry, and spinners lose to one common variant or another bar Starmie which has to play guessing games to avoid getting trapped / Voltturned.
Yeah that Mew set makes sense too; it just needs Taunt to do the work, I listed that set to give a rough idea but it's likely that it's not the standard and something else is better / more used/ etc.
Anyway, Xatu is indeed very good against the most used sets, but Electric Gem Suicide Lead with Thunderbolt 2HKOs always on the switch (well if SR are on the field, Electric Gem is not even needed). I never saw one, to be honest, but since it's listed onsite I guess it deserves a mention, too.