Clawitzer @ Choice Scarf/Life Orb
EVS: 252 Spe / 252 Sp Atk / 4 HP Scarf
EVS: 252 HP / 252 Sp Atk / 4 Def Orb
Modest or Timid Nature
- Water Pulse
- Dark Pulse
- Aura Sphere
- Sludge Bomb/Ice Beam
I don't feel like you need the ice coverage when Sludge bomb covers grass as well, but also Fairy types which are for the most part tanky and more of a threat, so having a wall breaker for them is always great, Ice Beam offers coverage for Ground and Flying types instead so it depends on what your team is lacking for coverage tbh. Water Pulse and the rest seem self explanatory to me, maybe except Dark Pulse, which I personally like for Dragapult, Aegislash, Indeedee and others. The item depends on if you want it to sweep or not, even with Choice scarf the speed will be rather mediocre, but it is viable if you feel like you're lacking major speed control. Life Orb is the item you run for most damage (unless you're confortable with Choice Specs) but you'll only work as a wall breaker then (which isn't bad, just a limitation) since you won't outspeed anything.
I run a different set for doubles, it's pretty much a gimmick but I kinda like it.
Clawitzer @ Choice Specs
EVS: 252 HP / 252 Sp Atk / 4 Def
Modest Nature
- Water Pulse
- Sludge Bomb
- Aura Sphere
- Dark Pulse/Flip Turn
YES it's a full on wall breaker, this gets you a whopping 558 Special Attack, you can run it with Life Orb if you feel more comfortable tho, but what do I do about speed? I run an Alakazam with full speed investment that learns Speed Swap. This allows you to pass a 383 speed Stat to your Clawitzer and make it a sweeping machine. You can do the same with Emolga, who learns both Speed Swap and Tailwind, but can't work offensively like Alakazam if for some reason you can't setup. With tailwind alone you'd have to invest EVS on speed to make it actually outspeed things (so Clawitzer wouldn't be bulky enough). About the moveset, Sludge Bomb is especially good in doubles since Clefairy and Togekiss can't use Follow me safely, but if you need the Ice coverage go for Ice Beam (since it also hits Togekiss just as hard). Flip Turn in case you want to use it as a revenge kill move against very low Pokemon and to switch into a safer Pokemon, pretty good with Choice Specs since you don't get stuck in one move,but it will take away from your coverage. You can use this strategy with Vikavolt too for example.
FINALLY, a set I wanted to make work for doubles but couldn't, I think it had potential tho
Clawitzer @ Blunder Policy
EVS: 252 Sp Atk / 252 Spe / 4 HP
Modest Nature
- Muddy Water
- Aura Sphere/Focus Blast
- Dark Pulse
- Sludge Bomb/Ice Beam
Muddy Water hits both opponents as a 90 base power STAB, doesn't hit your allies, but it's accuracy isn't the best. If it misses one of the enemies, Blunder Policy gives you a double speed boost (same for Focus Blast if you're that desperate for the speed, but that's very risky). Make sure to give it an ally that can protect it or disable enemy mons with finches or whatever. Anything with Helping Hand also helps since you have nothing to increase damage output besides EVS and nature (which already gives it a really good Sp Atk but sometimes not enough).
