A take, commonly used as a comical reaction to a surprising sight, in which someone casually sees something, briefly stops looking at it, realizes what it is, and snaps attention back to it with an expression of surprise or disbelief
I swear I did a double-take when I spotted that $100 bill lying in the gutter!.
A delayed reaction to an unusual remark or circumstance, often used as a comic device. do a double take to look at someone or something again because you are very surprised by what you saw or heard