On Saturday, a house caught fire in Fresno, California, and a woman on the sidewalk started screaming that her elderly father was still inside, hooked up to his OXYGEN tank.

Which is when some guy casually walked toward the fire and went inside.  Then about 30 seconds later . . . he came running back out with the dad on his SHOULDER.

And while everyone was checking on the dad . . . the guy who saved him VANISHED, and no one seems to know who he was.

There were also a couple other guys who ran in.  But he's the one who pulled the guy out.  All we know is he looks to be Hispanic, in his 40s or 50s, and was wearing a Dodgers hat.  And a woman got it on video, so there IS a shot of his face.

By the way, the fire did about $100,000 worth of damage.  But no one was killed.  And the dad was treated for smoke inhalation, then released.