It was mentioned in Island of the Giant Pokémon that James received Koffing, who had already been captured at this point, as a gift last Christmas (oseibo in the original Japanese version), before he met Ash. It is unknown who gave it to him.
Weezing first appeared in Pokémon Emergency! as a Koffing. James used it alongside Jessie's Ekans to quickly overtake the defenseless Viridian Pokémon Center. Koffing's job was to create a Smokescreen while Ekans destroyed the computers. Chasing everyone into the back room, Koffing and Ekans accompanied their Trainers in intimidating Ash, Misty and Nurse Joy, which caused Misty to decide to battle Team Rocket. This was a failed effort, however, as both of them managed to catch up to Ash in no time at all. However, Nurse Joy's Pikachu came out and healed Ash's Pikachu with a Thunder Shock attack, while at the same time attacking the Team Rocket trio. Giving Ash's Pikachu enough power to stand up, Ash charged up Pikachu using Misty's charred bike, and he let him use his own Thunder Shock. As the group were electrocuted, Koffing used Smog, and the electricity climbed up the toxic gas, causing the entire Pokémon Center to explode, and sending Team Rocket blasting off for the first time.
It was used constantly by James as his main battling Pokémon throughout Kanto and eventually evolved into a Weezing in Dig Those Diglett!, along with Ekans, after James and Jessie were desperate for them to evolve.
In Princess vs. Princess, Jessie used Weezing during the Queen of the Princess Festival contest. Weezing helped Jessie make it to the finals, but ultimately failed against Pikachu's Thunder Shock.
In The Evolution Solution, James used Weezing to capture a Shellder he dug up. Weezing was easily able to defeat it with its Haze attack after dodging its Ice Beam. Just as James was about to catch it, Jessie jumped in and got it herself.
Throughout the Johto region, James tended to use Victreebel more for combat than Weezing. During this time, Weezing was mainly used to create smoke to cover escapes and entrances.
Weezing fighting alongside Arbok
In A Ruin With A View, James sent out Weezing alongside Arbok to battle Team Magma Grunts who approached them. Not long after being sent out, Team Magma's Houndoom used Roar to send Weezing and Arbok back into their Poké Balls.
In A Poached Ego!, Team Rocket found a poacher holding a herd of Ekans and Koffing captive in Hoenn. After freeing them, James and Jessie reluctantly ordered Weezing and Arbok to stay in the wild and guard their fellow Pokémon. Arbok and Weezing had to when the poacher used his Tyranitar to attack Jessie, James, and Meowth, even though it was clear that they wanted to stay and defend them. The two Pokémon have not been seen since then. In this episode, James said that "Weezing and I are like brothers," indicating a great bond between the two.
Personality and characteristics
Weezing was shown to be extremely loyal to James, caring about him a great deal and only taking orders from him. In Island of the Giant Pokémon, as a Koffing, it refused to attack Ash's Pokémon on Meowth's orders, simply because he was not James. Both Koffing and Ekans were very sad about being separated from their Trainers, and were happily crying upon being reunited with them. Also, in that episode, when Meowth orders Koffing and Ekans to attack Ash's Pokémon, they refuse, and they revealed that "Pokémon not bad guys! Pokémon do bad things because masters bad!" This shows that while Weezing and Arbok have strong bonds with their trainers, they never see themselves or any other Pokémon as bad guys; they only carry out evil deeds out of obedience to their Trainers. In Dig Those Diglett!, Koffing's evolution into Weezing was triggered simply by James's emotional tears. The only time Weezing refused to obey its Trainer was in A Chansey Operation, where it refused to attack a Chansey because of how it cared for it during its operation from an injury that was caused from Team Rocket's scheme of stealing a group of Pokémon from a Pokémon Center going wrong. This also shows that Weezing will show a great deal of gratitude to anyone who helps it from any form of circumstance. As seen in The Flame Pokémon-athon!, even though Weezing will only obey James, its loyalty does extend to the team as a whole, and it will readily protect anyone it considers an ally. It demonstrated this by stepping in when Arbok was surprised by Ponyta's flames and retaliating with Smog, even though this proved to be a bad idea when the flames ignited the Smog.
Weezing is also shown to be very emotional, especially in situations when it was either seperated or forced to be seperated from James. In Island of the Giant Pokémon, when it was a Koffing and seperated from James, it became visibly upset (even changing its natural happy facial expression to worrisome) when Ash's Bulbasaur told them that their trainers abandoned them, and it and Ekans cried desperately with Ash's Pikachu trying to cheer them up. In Lights, Camera, Quacktion both Weezing and Arbok got depressed for being rejected as the main characters in the movie. It was only with James's and Jessie's help that they got over it. On their last appearance, in A Poached Ego!, they were reluctant in leaving Jessie and James, and when they did, they were in tears about it.
Weezing could be seen as extremely powerful in the first movie, as Nurse Joy and Miranda said more than once that only the stronger Pokémon with the most exceptional Trainers could face the storm. Yet, it was Weezing who brought Team Rocket to New Island.
| Using Poison Gas as a Koffing
| A † shows that the move was used recently, unless all moves fit this case or there are fewer than five known moves.