The Well Wizard was a character that appeared in the Smurfs cartoon show episode "Swapping Smurfs". According to Papa Smurf, he was the most ruthless sorcerer in all the land who used his evil magic to trap his victims within a well. In order to save the Smurf Village, Papa Smurf cast a spell on the wizard and trapped him inside his own well, having it sealed up so that nobody would think of using the well and falling prey to the wizard trapped in it.
In the episode, Lazy was the first to encounter the wizard when he went to sleep at the place called the Magic Swapping Well and through the wizard had his old torn pillow replaced with a new pillow with a completely different design. This led him to having the other Smurfs come to the well to trade in all their old things for new things. Unfortunately, Hefty got too careless and tossed Sassette's old Smurfy Lou doll into the well against her wishes, which made her very upset because the new doll she got wasn't like the old one. Grandpa Smurf asked the wizard if he could have Sassette's old doll back, and the wizard refused to do so unless he was given Papa Smurf's Smurfy Book Of Spells in exchange. Grandpa Smurf refused to do and instead went down to the bottom of the well with Snappy and Hefty, only to come back out of the well hypnotized under the wizard's spell.
Papa Smurf found out that the Well Wizard was now controlling the Smurfs that went down into the well and were abducting more Smurfs so that they could also be hypnotized to serve the Well Wizard's bidding. Realizing that the Well Wizard was after the Smurfy Book Of Spells from which he could find the spell that would free him, Papa Smurf altered the spell book and allowed it to be given to the Well Wizard, warning him not to turn to the green page for it contained a magic spell so powerful that no wizard is able to contain it. The Well Wizard fell for the bait of using the spell that was on the green page, believing it to be the spell that would free him, and instead cast a spell on himself that would seal him forever inside the well while freeing the hypnotized Smurfs from his control.