underworldlive.com hacked/malware?

[darmok]

This is the kind of popup I'm getting - but it seems to happen rarely, and is easiest to trigger when I visit from a new IP. Unfortunately I failed to capture exactly what's doing it here this time, and I can't get it to trigger again.

I'm positive it's not client-side - I've seen this multiple times on multiple computers, but only on underworldlive.com .

I'll keep trying to see if I can get it to happen again.