Albacore
sludge bomb is better than sludge wave
Thing is, it doesn't need to go mixed thanks to Secret Sword. So it can just invest in bulk to live Bullet Punches.+2 = 2 x 2 = 4, meaning you outspeed everything without needing to invest in Speed (well, at least effectively go mixed)
252 Atk Adaptability Mega Lucario Bullet Punch vs. 252 HP / 4 Def Slurpuff: 216-256 (58.6 - 69.5%) -- guaranteed 2HKO
And in return, Slurpuff OHKOs with any of its moves.
Gets wrecked by Banded Scizor, though. Although non-banded variants are beaten by Flamethrower variants.
Actually, it doesn't need to invest in HP, just Defense, since the only existing special priority can't touch it at all.
252 Atk Adaptability Mega Lucario Bullet Punch vs. 4 HP / 252 Def Slurpuff: 168-200 (54.9 - 65.3%) -- guaranteed 2HKO
Okay, it's only very slightly better, so perhaps not. But it's justifiable.