Im only getting Stronger!
Serperior @choice specs
Trait: Contrary
EVs: 252 speed 252 special attack 6 HP
[Nature]Modest
-Leaf storm
-Dragon Pulse/leech seed
-Giga Drain/Dragon Pulse
-HP ice/fire/rock/ground
Leaf Storm is pretty much self-explanatory, because, why not ? Every other contrary set has it, it works well with it, and heck, who doesnt want to raise their pokemon's stats to the maximum possible? Dragon pulse hits everything except for steel (and fairys), and HARD from the leaf storm boost. Leech seed would also work, because this serperior set tends to be fragile. Giga drain too, because sometimes, you just cant get by with the little HP leech seed gives you. Finally, a HP of your choice to finish up any other possibly dangerous pokes. HP fire is suggested for those who run Dragon Pulse, so then, you hit LITERALLY everything. Ice is also useful to hit those flying, dragon and other serps. Rock hits all of serp's weaknesses, and ground cripples heatrans who otherwise cripple serperior.
Weaknesses: Heatran, Blaziken, HA talonflame...
^^ Switch out when you encounter those pokes. DONT EVEN TRY. Heatran resists everything serp deals out, Blaziken kills, and Talonflame outspeeds serp with supereffective flying type moves + gale wings.