Serperior is my favourite Pokemon, so when this was revealed 2 days ago I was ecstatic that Serperior finally got the ability it had been wanting for ages. We discussed about it on IRC but I hadn't made a post about it, so I decided to now ^.^. Unlike any other OU viable Pokemon, Serperior can double its Special Attack while attacking at the same time, and this point is so crucial it completely turns Serperior upside down. Most Pokemon have access to reliable STAB and a powerful STAB move, like Keldeo's Scald vs Hydro Pump, or Latios's Dragon Pulse vs Draco Meteor (Dragon Pulse isn't common but I'm using it as an example). Where Serperior differs is that its powerful STAB move not only is its reliable STAB move (well, outside of 90% accuracy which really isn't too bad) but it also gives it a great boost which turns it from a terrible Pokemon into a remarkably unique threat. Serperior doesn't gain momentum and trade it for power. It gains more momentum and power at the same time. Leaf Storm is mandatory, of course. With Contrary Leaf Storm, Serperior has amazing value against defensive teams as it typically takes advantage of and beats common answers to special Pokemon, like Chansey, Unaware Clefable, and CM Mega Sableye. Dragon Pulse hits your fat Dragons which Leaf Storm is resisted against, like Dragonite, Garchomp, Kyurem-B, and the like. The a Hidden Power; HP Fire for Mega Scizor and Ferrothorn, HP Ground for Heatran, and HP Rock for Mega Charizard Y. The last slot is filler; Sub is an option but SubLO isn't completely desirable. Giga Drain is probably better, for gaining recovery and not wanting to risk a miss against like a last mon full health Rhyperior or something. I think it's possibly even better than Mega Sceptile; it doesn't take a Mega slot, can boost its power, and hits harder, though it misses out on better Speed and STAB on Dragon Pulse, as well as the ability to hit Heatran. Speaking of Speed, Serperior actually has really good Speed; it beats out Keldeo, Latios, and Gengar. Its bulk is good too, giving it even more benefits.