What do you call a cloud that is a spy?

This weather-themed joke cleverly uses wordplay to deliver its punchline. The humor hinges on a pun, where the word "mist" (a type of cloud or atmospheric water vapor) is combined with the common honorific "mister" and the concept of a "spy." The phonetic similarity between "mist" and "mister" is what makes the joke land, creating a silly and unexpected twist on the idea of a clandestine cloud.

Mist itself is a fascinating atmospheric phenomenon, essentially a thin fog or a cloud at ground level, often associated with a sense of mystery or obscured vision, which perfectly complements the secretive nature of a spy. Spies, of course, are known for their stealth and ability to blend in, much like a cloud can appear and disappear. This joke takes these familiar elements and playfully combines them, proving that even something as mundane as the weather can be ripe for a good chuckle through linguistic trickery.