Hey there everyone!
Okay, I think I've struck gold. In the past, Slaking has always been a heavy hitter, yet it's ability would really screw it over. While it didn't get any Dream World abilities, I think it can be a massive threat in this generation.
Here's my idea:
Slaking @ Choice Band
Truant Ability (just to emphasize it has no Dream World alternatives)
EVs: 252 ATK, 252 SPD, 4 HP
This set is honestly the ultimate revenge killer. Slaking with 419 Attack, Choice Band, STAB'd Retaliate (which power doubles if a Pokemon fainted before Slaking was switched in) will kill ANYTHING. It is not only the ultimate revenge killer, but can be a crazy wall breaker.
Pursuit is also a highlight of this set. Pursuit's power will double if the opponent attempts to switch out, which essentially adds STAB to it. With insane attack and a Choice Band, it deal a ton of damage.
The other two moves are really fillers. Let me know if you have better ideas.
Sorry, I mistakenly posted this here. I'm sure a mod will move it to the competitive section soon.