Weezing

Type Tier
Poison UU
Statistics
Stat
HP
65
333
Atk
90
278
Def
120
338
SpA
85
268
SpD
70
238
Spe
60
218
Name Item

Mixed Attacker Weezing

Leftovers
Moveset
~ Thunder
~ Fire Blast
~ Sludge Bomb
~ Explosion

I led with this on an underused team to some success. Thunder and Fire Blast take care of Steel and Water Pokémon (making it handy against the Spikers), Sludge Bomb has STAB and runs off of the decent attack, and Explosion is just a great move in general for taking out stuff.

Other Options

Destiny Bond isn't seen much, but could be nice to snuff out a Curser who's about to sweep your team. Curse and Screech are there mainly to boost Sludge Bomb's power and maybe get a switch. Pain Split can work decently with Curse for a pseudo-recovery move, and Haze could help for Cursers—Haze and then go kamikaze when they're about to kill you.

Opinion

Decent underused Pokémon with good attack stats in both categories, however beaten by Muk in just about every way. No Will-O-Wisp or Levitate makes GSC Weezing less popular than his RS counterpart. Explosion is always nice though.

Counters

Rhydon, Golem, Gengar all resist Sludge Bomb, and the first two also resist Weezing's other offensive moves. Misdreavus can be tough to face. Nidoking/queen, Donphan, Sandslash also resist Sludge Bomb. Alakazam, Espeon can both lay the smack down with Psychic, but Alakazam needs to watch out for Sludge Bomb damage.