Monster By Mistake! (partially found CGI animated series; 1999-2006)
Monster By Mistake! was a French-Canadian animated cartoon series that was broadcasted on YTV from 1999 to 2006. The plot of the series is siblings Warren and Tracey finding a spell book, which Tracey uses to accidentally transform Warren into a monster whenever he sneezes. When he sneezes again, he turns back into Warren. There is also a ghost who lives in the attic, who phases through doors to get into rooms, and who appears to be the spirit of a stereotypical 1950's gangster.
Information on the episodes is hard to come by except for a small synopsis of each episode on a Catapult Productions article.
Only 10 episodes have been uploaded to the internet, with the rest of the 45 episodes being lost. A few episodes have been released on DVD in 2004 by Genius Products, however.