You will Watch Invader Zim Episode 20 online for free episodes with HQ / high quality. Stream cartoons Invader Zim Episode 20 Door to Door The school is having a fund raising door to door candy sale with the promise of a ‘secret prize’ for the student who sells the most candy. (The candy is extremely hard to sell because it’s made up of sawdust. Zim: “Yup, that’s sawdust.”) Intrigued about what the prize could be, Zim attempts to sell as much candy as possible. Initially he fails, but he then utilizes virtual reality devices to torment innocent people and hence persuade them into purchasing his candy bars. Zim sells a huge quantity of the candy bars and wins the prize—only to find that there is no ‘secret prize’ and that it was concocted as a method of selling more candy cars.