STOPzilla was a computer program that the user would install on his Windows PC. It acted as if it detected or removed spyware, while all it did was being spyware itself, opening unwanted pop up windows, slowing down the system and so on. It was impossible to get rid of and cost a lot of money.
After a weekend of drinking beer, eating all those chilli dogs, poutine, and whatever else came in contact with your lips, shitzilla is what attacks you (usually on sunday evening) when you tremble as you approach the toilet.