>>16774087>Aegislashanything with knock off, pretty sure it will go before it activates and deny him the boost. his last move is probably sacred sword, in which case you can get him with sucker punch. bisharp is a good poke to use here.
>Gyaradosunaware quagsire does a good job, as you can fish for burns with scald and stop him from doing any damage once he's set up. he's super bulky and can scare away mamoswine with ease.
>Roseradeprobably the bulky set. scizor scares this thing away and gives you a free swords dance and opportunity to mega-evolve in the process.
>Mamoswinestarmie can OHKO with hydro pump and has the ability to spin away the rocks, but risks getting killed by EQ+ice shard if hydro pump misses. Air balloon excadrill falls just short of OHKOing mamo, but he can spin away the rocks once they're up and then outspeed with iron head for a kill.
>Noivernanything capable of taking a hit and using an ice type move. cryogonal can survive anything and everything noivern can throw at it and OHKO back, but only if it gets a safe switch in first. cryo also doubles as a spinner once mamoswine is gone.
>Gengarno idea, haven't played against it much. the smogon thread probably has some ideas for countering it, aegislash might be your best bet if you can get it to +2.