Journalist: "Can you prove beyond all doubt the moon isn't made of cheese? Have you confirmed it firsthand? Have you stood on the moon and tried to take a bite of it yourself?"
General: "What??? Uh, I haven't been to the moon, so I guess I'd have to answer no."
Journalist: "Moon made of cheese? Senior U.S. general says not ruling out anything yet"
'We're not sure what it might be', is very different from the usual 'No comment' that we'd been so accustomed to.
You'd wonder whether that's because of:
A: Misdirection B: Genuine uncertainty C: A new policy with which to address social media
But you know, just the need to shoot something down, disclose that fact publicly, but not reveal exactly what it is (even if it is just a terrestrial source), is pretty freaky.