Well, the moveset I am about to post only works if you have another pokemon in the team. I was hesitating at posting it, but pokemon is all about strategy so I thought I could post it. In order for this set to work, you need a Durant in the team with the Truant ability (although it is not released in the games, you can get it in the emulators). The Durant's set is this:
Durant @ Choice Scarf
Ability: Truant
EVs: 252 Atk / 252 Spd / The 6 remaining don't really
Jolly Nature (+Spd, -SAtk)
- Entertainment
- Whatever you want
- Whatever you want
- Whatever you want
Now, to the main point. When you believe your opponent is using a pokemon that can kill your Durant and it is NOT a flying type, does not have a Balloon or has the Levitate ability (It is easy to kill Durant with a fire type move), you use Durant. You go with Entertainment and the opponent will definitely attack with the fire type move the pokemon is holding, knowing that it can kill Durant. Then, the real deal comes! You use your mighty Dugtrio!
Dugtrio @ Focus Sash / Scope Lens
Ability: Arena Trap
EVs: 252 Atk / 252 Speed / 6 HP
Nature: Jolly
-Protect
-Hone Claws
-Earthquake / Substitute
-Stone Edge
So you probably have understood the way the set works. Dugtrio is the fastest pokemon with an ability that prevents switching. It can reach 372 Speed and that makes it a beast. As soon as Durant gets killed, you switch to Dugtrio. The first turn, the opponent's pokemon will be loafing around so you go with your Hone Claws. Then, you protect yourself while the opponent will be using an attacking move. And that can happen until you maximize your attack and accuracy. Afterwards, you start destroying your opponent's team and have fun. However, even if you maximize your attack there is the problem of the Priority moves and with its frail defense stat Dugtrio can be killed immediately. That's why I suggest to give it a Focus Sash.
Another option is to give Substitute, to help your hax Dugtrio protect itself from Priority Moves. If you are about to give Substitute I suggest to get rid of Earthquake instead of Stone Edge because if the opponent uses a flying type you can't do anything at all. Stone Edge is a Rock Type move and it can hit any pokemon. Plus, it will never miss thanks to Hone Claws and has a high critical hit ratio which can be abused if you give it Scope Lens (Focus Sash will be useless because you are using Substitute).