an attacking weezing can work, as it has impeccable coverage, and usage special attack:
Weezing@life orb
-Fire Blast
-Sludge Bomb
-Thunderbolt
-Pain split
252 hp EVs
252 SpA
4 defence
Now some calcs:
Weezing Fire blast vs Amoonguss: 78-91%
Weezing Tbold vs Almomola: 77-91%
And just in case fire blast manages to miss a ridiculous amount of times:
43-51%, comfortably outpacing regenerator
Amoonguss sludge bomb vs weezing: 15-18%
Almomola waterfall vs Weezing: 17-20%
(all calcs from kalashnikovs calculator)
thus, weezing comfortably beats the core