KnowYourMeme Wiki is currently used for documenting Users and Histories by the guy called EpycWynn with an assistance by me. My suggestion is to make the wiki itself disable anonymous editing to prevent further vandals or make someone who contributed there be promoted to be a local admin to prevent more vandalism, anonymous or not.
(Optional) - Contact CoolUsername321 and ask them to consider disabling anon editing for the wiki. Give them a week or so to respond if you are feeling generous.
Talk with Epyc Wynn about which of you (possibly both) should be promoted to bureaucrat (a bureaucrat can give admin rights). Once you guys have decided, contact staff with your request and include a link to your discussion. Also point out that there have only been 3 editors in the last year so agreement between the two of you automatically constitutes a majority of the current active community.
While waiting for staff to promote the user(s) selected from #2, if you guys cannot agree on who should be promoted, or if you guys decide to not promote anyone; contact VSTF if the vandalism gets serious.