Lanturn @ Leftovers
Trait: Volt Absorb
40 HP/136 SpAtk/252 SpDef/80 Spe
Lanturn is an adorable pkmn and Swanna can't really do much to it, thanks to the investment in SpDef, the calm nature, and the fact that it resists all of Lanturn's attacks. If Swanna stays in on Lanturn then it gets OHKO'd by Volt Switch. If it switches then momentum goes back to the player using Lanturn.