Quoted By:
Rain Dance Offensive set
252 Attack, 174 HP Or S.Atk, 84 Speed.
Adamant or Lonely
Waterfall or Scald
Earthquake
Ice Punch
Rain Dance or Stealth Rock
With 84 Speed EVs at level 50 Swampert outspeeds max 130s in rain.
Ice Punch is an OHKO 93.8% of the time on Mega Salamence, Confirmed OHKO After Stealth Rocks damage