Ekans is snake backwards, Arbok is kobra backwards, what is Muk backwards? O.o
Muk (M) @ Black Sludge
Ability: Sticky Hold
EVs: 212 HP / 252 Atk / 44 SpD
- Poison Jab / Gunk Shot
- Focus Punch
- Shadow Sneak / Payback
This guy is one of my favourite OG Pokemon, he is a pile of purple gelatinous substance, how awesome is that?
Anyway, Muk has decent defenses, high HP, and pretty good Attack, I think he does best with high powered moves to accentuate that attack. First, we have Poison Jab or Gunk Shot for STAB, the typical "power vs accuracy" debate, I prefer accuracy, so I go with Poison Jab. Focus Punch makes the set, it has 150 Power is isn't hindered by Muk's poor speed stat. Shadow Sneak has priority, is physical, and provides full neutral coverage with Focus Punch, it also hits Psychic types pretty hard; Payback is also viable, as Muk is slow, and it has almost as good a coverage, with a little more power. Substitute makes the set work as it protects Muk from flinching on Focus Punch, Muk can put up huge 101 Subs that can't be broken by simply Seismic tossing them.
EVs give it 404 HP (101 Sub), max attack, and a heightened SpDef for taking blows. Black Sludge is like Leftovers for poison types, I often use it to avoid Item Clauses, leftovers is also pretty much the same. Sticky Hold is the only worthwhile ability on this set as Stench is useless and Poison Touch doesn't work with two of the attacks...