Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Horrible!!!! Stay away!!!!

I bought these after seeing many good reviews on them. I did notice a couple bad reviews saying that the mat starts smoking the second you use it, and that unfortunately is true. I put it in the oven, at a temperature well within the guidelines, and after a couple minutes, I walked into my kitchen to smell a burning chemical. I opened my oven, and there was the mat with my pizza on it, just billowing (probably toxic) smoke. I have sent it back for a refund, and unless you want a nice "smoke maker" I would most definitely stay away from this cooking mat, all it's good for is smelling up your house and ruining your food :(. I am surprised Amazon still sells this, and I wish I could give it 0 out of 5 stars.