Castle Captor is the name of a haunted castle with a malevolent personality of its own that appeared in the episode "Lost Smurf". It appears at "the crossroads of the world" every 500 years to capture whoever is unlucky enough to venture close toward it, making them its prisoners and slaves to do its dirty work. Its appearance is usually marked with the skies turning various colors constantly and a cloud that appears at "the crossroads" that makes the castle appear from out of nowhere. To signal its disappearance, Castle Captor would make its walls become translucent before it disappears into the multi-colored maelstrom, then it goes away for another 500 years (with whoever is trapped inside the castle) with a few bright flashes and a bang. The castle would usually do its best to prevent whoever is trapped inside it from escaping before it vanishes.
During one of its visits, Castle Captor had captured a human prince, his guardian, and an elderly female Smurf named Nanny while she was trying to follow Grandpa Smurf in order to get more yarn for her knitting. During her time inside Castle Captor, she befriended a pink marsupial-type creature named Smoogle.
In the castle's most recent visit, while Castle Captor captured two human entertainers, Nanny had sent a message to whoever would be at the Smurf Village through a kite she had flown from one of the castle's windows. Wild Smurf found this kite outside his tree house and presented it to Grandpa Smurf, who knew where it came from and proceeded to rescue her from the castle in his magic balloon. Inside the castle, he found Nanny and helped her rescue the four human captives while also trying to rescue her "special friend" Smoogle. As they both tried to escape in the balloon without Smoogle, Papa Smurf and a group of Smurfs along with Smoogle were already at the top of the castle trying to escape disappearing with the castle. With Nanny and Smoogle's help, they all made it safely into the balloon and escaped before Castle Captor disappeared for another 500 years.