[A dude]

Marowak: With a personal item in Thick Club that doubles his attack, it definitely should be feared. It is indeed a bit slow, but pairing it with a Trick Room user or a paralysis supporter can compensate for that. It hits really hard off the bat, and can wreck anything that fails to make it faint. A personal immunity to Thunder Wave and a resistance to Stealth Rock is really helpful for him. Although Marowak needs a bit of support to help him do his thing, he is an absolute menace that would be Ubers material with Speed Boost or Huge Power. I wish this guy got Head Smash and Rock Polish; he would be absolutely terrifying.

The best set is the Substitute + 3 Attacks set, as Marowak has problems with durability. The set is simple: Set up Substitute on something seemingly harmless, like a Choice-locked Zebstrika, and let Marowak go on rampage. As for partners, fixing that speed is the best way to support it (Paralysis supporters like Natu/Lickilicky, etc.). There is no denying its horrible speed and a tad shaky defensive stats, but this thing's power is sick - watch this thing go on a rampage on paralyzed teams lacking Knock Off or Trick.