[WildAce]

GYARADOS:

Gyarados @ Leftovers / Life Orb
Ability: Intimidate
Nature: Adamant
Evs: 252 ATK / 232 Speed / 24 HP
- Dragon Dance
- WaterFall
- Earthquake / Stone Edge / Ice Fang / Return / Taunt
- Earthquake / Stone Edge / Ice Fang / Return / Taunt

Enter Le Sweeper.
Basic DD Gyarados....Sweeper style.

Although Gyarados is a Bulky Water (that can take Non-STABed TBolts), I felt that for the sweeper variant, it should fully focus on Speed + ATK.
The EVs given allow it to outspeed Weavile and Co. after just 1 Dragon Dance.

As for the last 2 moves, you can either go with 2 offense moves for that Pure Sweeper "feel"....or you can be smart and go with Taunt.
Now, why is Taunt so good you may be asking.

Taunt it excellent on certain Sweepers because it allows them to completely dominate the things that would otherwise Wall them (i.e. Skarmory, Non-Tbolt Weezing, and Non-TPunch Dusknoir).

Basically, after Taunt, you KNOW you won't be Phazed, Paralyzed, Burned, or otherwise left crippled.

As for attack type combos:
WF + Stone Edge is my personal favorite....but leaves you vulnerable to the likes of Metagross (who can't really do much to you anyways save Explosion).

WF + Return has it's merits as a type Combo that is resisted only by Empoleon.

WF + Ice Fang will allow you to easilly deal with Mence/Nite/Chomp, but will leave you vulnerable to Water PKMN.

Ice Fang/Stone Edge + EQ forgoes STAB, but provides you with Excellent Type Coverage.

Whatever you choose, make sure your team can handle what Gyara can not (and take care of THEM first before sending out this Blue Dragon thingie).

Gyarados @ Leftovers
Ability: Intimidate
Nature: Adamant
Evs: 212 HP / 16 ATK / 180 DEF / 100 Speed
- Dragon Dance
- WaterFall / Ice Fang
- Earthquake
- Taunt

Note: Complete Credit for this set goes to Jumpman16 from Smogon.com.

This is Bulky Gyarados.
The Evs given provide it with efficient Leftovers Recovery and allow it to outspeed all Non-CScarffed Garchomps after 1 DD.
The DEF + HP Evs are there to abuse Intimidate and allow for easier Set-Up with DD.

This set requires a bit more Prediction than the first set (which was just DD and Kill).
Furthermore, this thing needs to be played like DDMence was played back in ADV Gen...that is, guage your opponent first before even attempting a Dragon Dance Sweep (so you can wipe out the things that would otherwise wall this beast).