Bonus Ballot
From IdleOn MMO Wiki
The Bonus Ballot is a Yum Yum Grotto feature allowing you to vote for one of 3 buffs to become a worldside bonus for the next week, until the next buff is picked.
If the winning vote of the week is a feature later in the game you havent reached, like a world 4 bonus but you're still in world 3, you will get a 1.25x DMG bonus instead!