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

"What if" or "but what if" translates quite well as (でも)もしかしたら (de mo moshi ka shitara). "Moshi ka shitara" is used with a supposition very similar to English "what if".

Answer 2

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