The complete Pokemon RBY pokedex, part 10

Pokémon Name: Koffing
Type: Poison
Classification: Poison Gas Pokemon
Pokédex Number: 109
Ability: Levitate
Useful Attacks: Sludge
Location Found:
Diamond/Pearl: Breed Weezing
Platinum: Stark Mountain
HG/SS: Burned Tower, Safari Zone (Marshland); Pokewalker - Town Outskirts
B/W: Poke Transfer

Another one of Team Rocket's early favorites. It's tough not to smile at Koffing's Grimace-like face and chipper demeanor. Too bad his evolution looks like an abomination that needs to be put down. The longer he stays this way, the happier he'll be... though your trainer aspirations may force the evolution.

Evolution: To Weezing at 34