The Elephant's Foot is the nickname given to the large mass of corium beneath Reactor 4 of the Chernobyl Nuclear Power Plant, near Pripyat, Ukraine. The mass formed during the 1986 Chernobyl disaster from materials such as molten concrete, sand, steel, uranium, and zirconium. It is named for its wrinkled appearance and large size, evocative of the foot of an elephant.