interjection
what's that?; what the?; what's going on?
Casual interjection expressing surprise, confusion, or disbelief about something just seen, heard, or mentioned. Often used when encountering something unexpected or hard to understand.
え、何それ、聞いたことないよ。
Huh, what's that? I've never heard of it.
何それ、急にどうしたの？
What's going on? What's with you all of a sudden?
Combination of 何 (nani, 'what') and それ (sore, 'that'). A straightforward colloquial phrase.