Quoted By:
Strong Electric special attackers (there are plenty)
Strong Grass special attackers (Celebi, M-Sceptile pretty much.)
Stallbreakers like Mew
Physical set-up sweepers with a move that can hit Slowbro hard (e.g. +2 Mega Gallade can 2HKO wtih Knock Off after a bit of prior damage, Mega Altaria can 2HKO after 2 DD's)
Assorted stuff like Hydreigon, Unaware Clefable, SubDD Mega Gyarados, CroCune,
Lures like Grass Knot Mega Metagross, X-Scissor SD LO Terrakion, SubEndeavor M-Lopunny.
Taunt, Phazing, and Toxic in general, not to mention Haze and Perish Song.
Some of these depend on set so don't point out that CroCune loses to CM+Psyshock or whatever. Point is there's plenty of ways of handling it and, while it's a good mega, it's being a bit overblown.
