Use Camerupt with Slowking + Tangrowth. It absolutely owns Magmortar, Manectric, Galvantula, Accelgor...basically every special attacker that gives that duo trouble, Camerupt destroys. It makes the best FWG core RU could ask for. I prefer an offensive tank set (252 HP / 252 SpA, SR / Fire Blast / Earth Power / HP Rock), but defensive is solid too (252 HP / 252 SpD, SR / Lava Plume / Earthquake / Roar). Either way you counter the hell out of all those Magmortar and Manectric running around. Use it.