That Gliscor is EXACTLY what I was looking for when I chose Rotom, Don't believe I didn't think of it myself.
Also, Toxic on Gliscor allows me to keep explosion on heatran, so I'll probably go with
Heatran (M) @ Life Orb
Ability: Flash Fire
EVs: 4 Atk/252 Spd/252 SAtk
Naive nature (+Spd, -Sp...