Spread the Gibus throughout all player accounts.

The achievement called "Gibus Grab" has given the Gibus the means to spread. Dominate and kill all people equipped with unique hats, leaving only the players equipped with the Gibus left. Allow new players to dominate you to receive their Gibus, and then invite them to this group. If you're struggling with eliminating all the players equipped with unique hats, simply just go onto this group profile and invite a member from the group to assist you.