How to say “unless…?” in the context of “but what if”

Question

In the context of the phrase "Just kidding... unless...?", how would the word "unless" be translated? Here, "unless" has sort of a connotation of "what if...?" as well as "unless you want to?"

Answer 1

Or you can just use 冗談でした。。。けど。。。もしか。。。