This set is basically the same as the old calm mind+taunt set, but with a slight change to the EV's.
Here is the new set:
252 SpA/212 Spe/44 Hp
Held item-Life Orb/Leftovers
Moves
-Calm Mind
-Taunt
-Aura Sphere
-Ice beam
The new speed EV's give mewtwo 384 speed, just enough to outspeed max speed darkrai, while forfeiting the ability to tie with other base 130's (crobat, aerodactyl, and jolteon). But these pokemon are rarely seen in ubers (if ever) so it's of little consequence to mewtwo. The remaining EV's are put into HP to give mewtwo a little extra bulk (If this is a bad HP number for leftovers/life orb, a few EV's can be taken out of Hp and placed in special defense instead). This same EV spread should also be used on other attacking sets, because as stated earlier, mewtwo doesn't really need to worry about other base 130's. Anyways, the rest of the details of this set are the same as the old calm mind+taunt set so there's no need to repeat them here.
Here is the new set:
252 SpA/212 Spe/44 Hp
Held item-Life Orb/Leftovers
Moves
-Calm Mind
-Taunt
-Aura Sphere
-Ice beam
The new speed EV's give mewtwo 384 speed, just enough to outspeed max speed darkrai, while forfeiting the ability to tie with other base 130's (crobat, aerodactyl, and jolteon). But these pokemon are rarely seen in ubers (if ever) so it's of little consequence to mewtwo. The remaining EV's are put into HP to give mewtwo a little extra bulk (If this is a bad HP number for leftovers/life orb, a few EV's can be taken out of Hp and placed in special defense instead). This same EV spread should also be used on other attacking sets, because as stated earlier, mewtwo doesn't really need to worry about other base 130's. Anyways, the rest of the details of this set are the same as the old calm mind+taunt set so there's no need to repeat them here.