乖乖

When we use 乖乖, it's often in this way, "乖乖啊，不然打你屁股。"

Or, as a noun, "我的小乖乖，有没有想我啊？"

But did you know, other than the above, it can also be used as an interjection (叹词)?

"外面好冷啊， 乖乖，冻死我啦！" - akin to "OMG", "wow", and the such.