What is the "official" term for

First time I’ve ever heard of an elephant’s foot of kebab! I’ve only heard of Chernobyl’s Elephant Foot, which you probably wouldn’t want to swing at a car window either…

Chernobyl’s Elephant’s Foot is a solid mass of melted nuclear fuel mixed with concrete, sand and core sealing material. It’s located in a basement beneath the No. 4 reactor core.