This combines some of the ones I've already seen here, but I believe it outpowers all of them:
Ability: Arena Trap
EVs: 252 Atk, 252 Spd, 4 HP
Dugtrio uses Substitute, waiting for an opening, and uses Hone Claws as soon as he gets one. Liechi helps as he gets down to 25% HP. Hone Claws's accuracy boost also allows him to use the more inaccurate, but more powerful, Stone Edge.
If you're creative, don't copy and paste this into your signature (Started by 3.14kachu).