New OU/UU Lead: Shiftry @ Focus Sash
EVs: 4 HP 252 Atk 252 Spe
Ability: Chlorophyll
Nature: Hasty
Fake Out
Sunny Day
Explosion
Faint Attack
So yeah. Maybe this idea is flawed, but it seems to work pretty damn well in matches. Fake Out on turn one, Sunny Day on turn two, Explode the same turn your HP drops below 100% and Faint Attack until then. Faint Attack is there for those pesky Ghost-types who like to eat Explosions. If I see a lead that I know is probably carrying priority (e.g. Scizor, Machamp) I can forgo the Sunny Day and just explode, or switch out. EVs are obviously there to make the big kaboom hurt more. This would be incredibly epic in UU and I have no idea why no one's thought of it (and posted it) yet, but it still works decently in OU.
How it stacks up against other leads:
Azelf: Is dead. 100% chance. Unless, of course, he U-Turns to something else, in which case whatever he U-Turned to is dead. Sunny Day is up.
Aerodactyl: If he Taunts you he gets Stealth Rock up and you don't get Sunny Day up. Then he dies. If he decides to SR first instead of Taunting because he thinks you'll attack Sunny day is up and he's still dead.
Swampert: Exploding works like a charm. He can't Roar you out because if he does Sunny Day teams laugh in his face once Sunny Day is up. Which it will be if he Roars.
Metagross: Explosion might not kill it but boosted Fire moves sure as hell will the next turn. Sunny Day is up.
Jirachi: Abuse Faint Attack after a Sunny Day. If he kills you, you always have boosted Fire. If you get him below 60%, meaning two of Faint Attacks, an Explosion will guaranteeably finish him.
Infernape: Run like hell.
Machamp: Machamp tends to carry Bullet Punch, forcing you to explode before you can Sunny Day. Good news is that he doesn't get to set anything up either, and Machamp is dead.
Ninjask: Spam Faint Attack or switch to a Taunter and watch him scream.
Roserade: Um... hope that the sleep misses. If it doesn't, it's just as though I exploded on a Ghost-type. Again, boosted SE Fire moves.
Tyranitar: It's unfortunate that Sandstorm breaks your Sash. Then again, explosion puts a huge dent in this guy.
Scizor: Sunny Day, Explode, finish it with boosted Fire which is now set up.
Abomasnow: So Ice Shard means you can't put up Sunny Day right away. His hail inducer is dead. Who do you think won?
tl;dr: An epic Anti-anti lead, as well as slaughtering Azelf and Pert.