Although I was not able to find the IP that Zyl mentioned, I went ahead and put it into my Cpanel's IP Deny Manager anyway. I also added bakaserv.com, which resolved to 76.162.58.250, which was the IP that came up during a whois search.
I don't like to ban IPs for a long time, but if enough people banned this IP for a few weeks, it might at least help to annoy Tubeless. What kind of ads are they running now, so that the ad company can be contacted and asked to remove Tubeless as a member?