Well, we've definitely had that issue for a while.
Yes, that is exactly what it looks like... A bottle of holy water.
(And yes, that is a nasty pile of garbage below, that is NOT ours. It's our suitemate's, and they are lazy.)
Nobody knows where it came from, who brought it, or anything.
It's just been sitting around in our suite's common room for months now.
I guess nobody feels brave enough to throw it out.
I think I may be the only atheist-leaning agnostic here, but even I couldn't do that... It just feels wrong.
Perhaps this mystery will never be solved.