Just going to drop by and say that slower Pokemon will usually eat a +2 Z-Move which can mostly OHKO (looking at Volcarona, Heatran, Zapdos, Charizard). While they are fine as Checks, you have to keep the power Kartana boasts in mind.
someone else already used this!Reserving Bulky Volcarona
Volcarona @ Firium Z / Leftovers
Ability: Flame Body
EVs: 4 Def / 252 SpA / 252 Spe OR 248 HP / 196 Def / 64 Spe
Timid Nature / Bold Nature
- Fire Blast / Fiery Dance
- Quiver Dance / Will-o-Wisp
- Giga Drain
- Hidden Power Ground / Roost
Volcarona is a cool, er, hot, check to Kartana. If Kartana is at +2 though, watch out (hence this being a check), as standard Volc just dies to Z-moves, but Bulky Volc lives anything except +2 Black Hole eclipse.