Stallion
Tree Young
I voted Salamence, because it is so damn versatile and NOTHING can actually switch in properly on MixMence without losing a huge chunk of health. Just make sure you have a spinner, and Jirachi helps it alot with Wish + U-Turn. Second would be Tyranitar, especially the DDance set as common physical walls such as Gliscor, Weezing and Cresselia are easily 2HKOed (at the least) by it, and with DD + Taunt it lols completely at status. With a set like Fire Blast/Ice Beam/Crunch/Stone Edge (Life Orb), only Swampert can switch in on it reliably without risk of being KOed. Only thing that kept it away from the number one spot was low speed.