Endless Phaze
Salamence @ Choice Scarf/Leftovers
Overconfidence (or whatever its called) Jolly Nature
252 Atk/4 Def/252 Spd
-Sleep Talk
-Dragon Tail
-Fly
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Switch in on a Sleep move after your team has set up SR/Spikes/Toxic Spikes/Any debilitating Statuses. Use Sleep Talk to lay down Dragon Tail hax without having to worry about Rest failures. Best use would probably be keeping Salamence out for only 2-3 turns, and then withdrawing it if its still asleep- Gen V mechanics mean its sleep counter will reset. Then just bring it out every time one of your Pokemon faint, making sure to withdraw it before sleep runs off.
Overconfidence in case Dragon Tail gets a KO. Leftovers if you're REALLY worried about Stealth Rock and Weather, but this set is all about Speed, so Choice Scarf is basically a necessity. Priority can wear him down as well, but the only major one to be worried about is Ice Shard. If you have issues with that, use Intimidate as the ability instead. Fly is just there so if he wakes up and it looks like Dragon Tail isn't going to cut it, you have an alternative move to fall back on. (Sleep Talk won't select Fly)
Basically, to run this, you're going to need a team that is already capable of keeping the field clear of SR/Spikes/ETC, while setting them up themselves. You'll probably also need something to counter common Ice Shard users. Mischievous Heart users can also cause some problems, but I don't think they commonly carry the moves that are most deadly to this set. There is also the major issue of facing an opponent that doesn't run Sleep... so this set may not be worth it.
This set is definitely gimmicky, but its more reliable than the majority of gimmicky sets I've seen. If you can get it to sleep, and are lucky enough not to have 1 turn of sleep, the effort of setting it up will more than pay for itself, and even if you can't get SR or spikes down, a couple of stab Dragon Tails every time one of your Pokemon goes down will quickly add up.