Koffing might not be the strongest but it has the best assurance of a side
affect other than those auto sleep or poison Pokemon attacks.
HP: 50
Weakness: Psychic
Resistance: None
Retreat cost: 1 Colorless energy
Attack: 1 attack-2 Grass Energy
Foul Gas: Flip a coin if heads the Pokemon is now
poisoned; if tails the Pokemon is now confused.
Since both sides of the coin do a certain side-affect, there is almost no way
you can't cause significant damage to that Pokemon (at least you do damage
with poison if not with confusion).
Master1080