They used to make these things called “Shrinky-Dinks”, which were sheets of thick plastic that you would color with pencils, then cut them out and stick them in the oven and they would shrink down to a smaller size.
Well one day when I was 3, I decided I could do this by myself, except that I put them in the toaster oven on the grate on like 400 degrees. Of course that shit melted through the grate and onto the heating element inside the toaster oven. Thankfully my parents noticed the smell before a fire started. Not sure how much a toaster oven cost in the '80s, but they had to get a new one one.