What (in) the devil?
and What (in) the dickens?Inf. What has happened?; What? (Often with the force of an exclamation.) What in the devil? Who put sugar in the salt shaker? What the dickens? Who are you? What are you doing in my room?
What the devil?
and What the fuck?; What the hell?; What the shit?What has happened?; What? (Often with the force of an exclamation. What the fuck? and What the shit? are taboo.) What the devil? Who put sugar in the salt shaker? What the fuck? Who are you? What are you doing in my room? What the shit are you doing here? You're supposed to be at work.