Keep resolving, but instead of resolving multiple A records, resolve just one. Fuck that one server in particular.

Delay updates by 1 week.

Answer randomly with the up-to-date or the out-of-date records.

https://en.wikipedia.org/wiki/Work-to-rule

Then you're harming your own customers/users as much as anything. They probably don't want to do that.

Resolve to porn.