The video is said to be from a closed-circuit security camera taken Sept. 11 at Cilandak Town Square in South Jakarta, the Web site wnd.com reported Sunday.
A bright flash of light appears to come down to the ground, then jump back up and out of frame.
The narrator of the video provides a slow-motion version and describes seeing what looks like a humanoid with "what appears to be some type of wings or something."
"And you can see the pulsating. … It looks like a butterfly. … I think it's an extraterrestrial," the narrator says. "An extraterrestrial means simply from another dimension so it doesn't have to be a negative thing right away.
"It's very strange. I almost want to say that it is extraterrestrials or when people come out of their body. That's the way we look like. It's a man in there. I want to say that it's naked, it had no clothes,"
Then, what are said to be security guards come in with flashlights to investigate the scene.
Some commentators on YouTube say the flash of light is an angel, while others say it's nothing more than a hoax.
"First of all, we have one static picture, on which picture of alleged 'light being' is mounted," one poster said. "Nothing in that lobby moves except it. And then suddenly, after it disappears, we see a man in lower right quadrant of video who is walking by, who has suddenly appeared in almost middle of frame,coming from nowhere, apparently unbaffled by appearance of huge winged light creature in front of his undisplayed path. And creature illuminated entire floor of that building. Eh."