Prions are a type of protein gone wrong. The complex three-dimensional structure of a prion’s progenitor protein has been altered, somehow causing it to no longer function as expected. Worse, the malformation of these progenitor proteins into prions causes them to aggregate into amyloid plaques that can result in a disease state. Prions are responsible for an odd sort of protein-caused infectious neurodegenerative diseases like Mad Cow disease and scrapie in livestock.