Mycotoxins are like very gross and yucky chemicals that are made by some kinds of mold. Mold is a type of tiny living thing that grows on things like food or walls when they get damp or wet. When the mold makes mycotoxins, they can be very dangerous if people eat or breathe them in. They can make people and even animals very sick! That's why it's important to keep things dry and clean, so that mold can't grow and make mycotoxins.