This morning I found out one of my subdomains was hosting a scammy website because I had pointed the CNAME to GitHub pages but no repo was configured to serve off it. So some spammers/scammers made a repo (can't figure out which one) and took over. I only found out because they decided to even register it on Google search console, which in turn alerted me that a domain of mine had new admins.
Took me 30 mins to figure out what the hell was going on.