porygon2 also works rather well ive found, if he tries to stall porygon2 gets boosts as well, and can magic coat toxic back and thunderbolt for super effective damageYou mean octillery right?
Also another good counter unless it gets banned is Manaphy with energy ball, since it can tail glow on the protect and wipe out Oct every time. With no reliable recovery unless it gets like +6 sp.att in a row Manaphy will eventually beat it.
Taunt users can force it out too, i run a MH sableye which has stopped it dead a couple of times
however if he swaps in on something that cant touch it and it gets +2 SpAtk on the first turn it can be harder to deal with