Sticky, wet stuff can refer to a variety of substances, such as GOO, TAR, and GOOP. GOO is a thick, viscous liquid made from cornstarch and water. TAR is a black, sticky substance made from the distillation of coal, wood, or petroleum. GOOP is a brand name for a line of products that are used for cleaning, lubricating, and protecting surfaces. All three of these substances are known for their sticky, wet properties.