Why its the explosive elf, Azelf! Now, most people would say that it's mostly outclassed by Mewtwo, and this isn't far from the truth. It's slower and less powerful on the Special side. HOWEVER, Azelf has a few tricks up its sleeve that ensure that its not totally outclassed: mainly, U-turn, Stealth Rock, Levitate, and Explosion!
Set 1: Choice Scarf lead
Stealth Rock
Trick
U-turn
Explosion
Jolly, 252 Atk 252 Speed 4 whatever
satus: tested, verdict unclear
Alright, this is a lead I tested a while ago with some pretty fuzzy results. The concept here is that besides the Deoxys family, Azelf is the only Trick Scarfer that has Stealth Rock AND is faster than Deoxys-S! So you just trick Deoxys-S (and pray to GOD it doesn't start Spiking), and then either set up your own Stealth Rock, or U-turn because it taunted you. You can also U-turn away from thoes pesky Deoxys-A, and from Darkrai if you make the guess that it doesnt have a Scarf! It can also Trick Groudon and not die in the process!
The good news ends here though, because while Azelf does well against a selection of leads, it did HORRIBLY against others. Dialga just Draco Meteor'd its ass to hell, while Kyogre smashes it with Surf. Scarf Darkrai murders it, and Skymin flinches it to death. Some more obscure leads like Tyranitar also eat it for breakfast. Finally, Giratina-O owns this thing with its immunity to trick and Shadow Sneak.
Overall, this lead gave me some very mixed results. It did very well against some other leads, but failed hard against some others. I will test it again later, but for now, the results have been a mixed bag.
I'll post some other Azelf sets to test later, because somehow I feel that Azelf has more potential than it seems...
Jibaku EDIT: Careful about Scarf Deoxys-S lol. Not only will it throw Spikes around it will also lock you into Trick.
