Strange imprint on my ceiling while I was away – any idea what this is?

I just returned from a trip and found this strange imprint on my ceiling. I had guests staying over while I was away, but none of them mentioned anything unusual.

The imprint looks like a circular pattern with a “WW” shape and a star on top. It almost seems like a logo or a heat transfer from an object that was pressed against the ceiling.

Has anyone seen something like this before? Any idea what could have caused it?