For those who abide by the "if you don't eat it, don't put it on your skin" rule, this is an unusual exception in the form of a DIY mascara that can be made from Oreo cookies. The tutorial from YouTuber Katharine of xxmakeupiscoolxx involves mashing up the dark cookie part of an Oreo to a fine powder and then combining the remains with water and some face primer.
Once the consistency of "cake batter" has been achieved, the mixture can be transferred into a container for storage. Since the mascara is made from a perishable food item, it probably doesn't keep as well as commercial mascaras. When it's time to apply this DIY mascara, it can be applied with a plain mascara wand for lashes as dark as an Oreo cookie.