Huge dump? Big puke? Quick sweat session??

That's the question everyone is asking after the UFC star miraculously made weight for his UFC 210 fight after a nearly missing the cut at the official weigh-in Friday morning.

Long story short ... Cormier weighed 206.2 at his initial weigh-in -- 1.2 pounds over weight.

He left the room and came back 2 minutes and 24 seconds later ... and somehow, weighed in at 205 exactly. The fight with "Rumble" Johnson is now official.

But everyone wants to know what changed in those 2 minutes. Some conspiracy theorists think he grabbed the towel that was shielding his naked body and pressed down to fool the scale.

For the record, event officials have called BS on that theory.

We've reached out to D.C. for answers. Stay tuned.