Rotom-M @ Leftovers
Ability: Levitate
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Leaf Storm
- Confuse Ray
- Thunder Wave
- Thunderbolt / Thunder / Volt Switch
Leaf Storm is a great Grass-Type move, with that nasty SpA drop.
Confuse Ray + Thunder Wave is what my shiny Mow-Rotom has in my X game, and it has saved me in many WiFi battles, it is an annoying combo.
The last slot is really your choice. Thunder if you want power, Thunderbolt if you want accuracy, or Volt Switch to get out of there. Volt Switch is nice combo with Leaf Storm, that way you can get rid of the SpA drop when you switch out, but at the cost of power.
You can also replace Thunder Wave or Confuse Ray with Will-O-Wisp if you want to wear down health and cut their attack. You can also give Rotom the move Trick, then give your opponent a choice scarf, or another choice item.