(emphatic) what on earth; what in the world; who on earth — an emphatic form of 一体 used in questions to express strong surprise or frustration.
一体全体、君は何を考えているんだ？
What on earth are you thinking?
この問題は一体全体どうやって解けばいいのか。
How on earth am I supposed to solve this problem?
一体全体、誰がこんなことをしたのだろうか。
Who on earth did something like this?