That's about where the information runs out. The photo that made it to the internet is blurry, or partial, or catching whatever-it-was mid-exit, and the post that accompanied it asked a question rather than answered one: Who the hell...

This is a specific kind of neighborhood moment — not a business closing or a mural going up, but the small interruption, the thing glimpsed at the edge of attention that makes someone stop walking and wonder what they just saw. Potrero Hill generates these occasionally. The neighborhood sits high enough on the east side of the city that you can see across to the bay, and the streets there have a quieter residential rhythm than the corridors closer to downtown, which means that when something unusual passes through, there's a decent chance one person catches it and the rest of the block misses it entirely.

What was it? A vehicle, an animal, a person in an unexpected costume, a piece of machinery being hauled somewhere unusual? The source material doesn't say, and without a clearer image or a follow-up from the original poster, it stays in the category of local curiosity rather than confirmed sighting.

Someone walking on Potrero tomorrow would notice nothing. Whatever it was has moved on, or gone back to wherever it came from, or is sitting in a driveway somewhere being entirely ordinary. The only trace is a blurry rectangle on a phone screen and a question that didn't quite get finished.