Thingmaker, also called Creepy Crawlers, is an activity toy made by Mattel, beginning in 1964. The toy consists of a series of die-cast metal moulds resembling various bug-like creatures, into which is poured a liquid chemical substance called "Plasti-Goop", which comes in assorted colours. The mould is then heated to about 390 °F (199 °C) in an open-face electric hot plate oven. The Plasti-Goop is cured by the heat, and when cooled forms semi-solid, rubbery replicas which can be removed from the mould.