Monster by Mistake is a Canadian

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 computer-animated television program aired on YTV. The story deals with an eight-year-old boy named Warren Patterson and his older sister Tracy, as they deal with bullies, ghosts, magic and an irate sorcerer.

Synopsis

One day, the two siblings discover a creature named Gorgool in a glass-like ball. He attempts to trick them into freeing him by reading out of a book of spells and using the power of a magic jewel, but Tracy reads the spell wrong, and the spell hits Warren instead. This spell causes Warren to turn into a large blue monster whenever he sneezes. To return to his regular state, he must sneeze again. Warren has allergies, causing him to sneeze a lot, which in turn causes him to change into his monster form frequently. Gorgool manages to obtain a servant after Warren and Tracy foil his first attempt to escape. The servant is large, clumsy and not very intelligent. He is also referred to as Servant.

The series deals with Warren and Tracy guarding the book and the jewel in order to keep Gorgool imprisoned while avoiding a bully, Billy Castleman and their police aunt Deloris, who is obsessed with capturing the Monster; their father is convinced that it is just a guy in a costume. They are accompanied by a jazz-playing ghost, Johnny B. Dead.

Fenrath

Later on, in the third season, the kids and Johnny go to Gorgool's planet, Fenrath. In Fenrath, they make a friend named Red who accidentally learns of Warren's secret. When they visit Fenrath, they are also troubled by Gorgool's twin brother, Morgool, who rules Fenrath. Unlike Gorgool, Morgool isn't confined to a ball, and is far more dangerous. He also has a guard working for him named Kragon.