The most common version is
(M) Riolu
Trait: Prankster
@ Focus Sash
~Roar
~Copycat
~Protect/filler
~toxic/filler
You have to have a diffrent pokemon set up stealth rock, (and spikes the other hazards if you want) then send in Riolu when one of your team members faints, survive the hit with the sash, and use a phazing move. I've seen circle throw on it as a "just in case" situation, but it's not necessary.