Wanda Grubwort is the main antagonist in Scooby Doo! Curse of the Lake Monster. She was a witch from the 1800's when some settlers who landed on her territory She told them to leave. They ignored and she put a spell on some frogs turning them to monsters. They attacked the villagers strangling one man to death. She was tried and was burned for her witchcraft, where her spirit lay in the moonstones of her staff, waiting for revenge.
Grubwort's Revenge
Wanda Grubwort returned when her moonstones were discovered by the Mystery, Incorporated. gang. She possessed Velma when she touched her first moonstone and had her search for the others. Along the way, Grubwort used Velma to sabotage the gang's attempts to discover the secret of the Lake Monster, her own monster of a frog which she created years ago, who has come back to wreak havoc on Daphne's uncle's country club. Fred and Daphene find out Wanda had children. They believed that her descendants wanted revenge, Her descendant has one of the moonstones and the other was hidden in a sand trap. She takes the moonstone Shaggy found and raids her descendant's house looking for the last moonstone. There, the gang learn that Grubwort is possessing Velma and her descendant helps the gang stop Grubwort for re-obtaining her power. The gang use scuba gear to get into Grubwort's underwater cave, where they see Grubwort turning three more frogs into monsters like her other monster. Fred and Daphne are chased by the monsters while Shaggy and Scooby try to help Velma fight Grubwort's spirit. It finally works when Shaggy expresses his love for Velma and they free her with the moon song. However, Grubwort was still alive as a ghost, and tries to summon her moonstone staff to her, but Scooby fetches it and destroys it, turning the frog monsters back to regular frogs and Grubwort's ghost exploded, before saying she would have gotten away with it if it wasn't for the meddling kids and their rotten dog.