The Halloween event is a seasonal event that triggered October 2021. Contrary to the sport event, players had 24 hours to complete one round instead of 3 days. Until November 3rd, it was possible to replay the event as many times as possible - after that, it got deactivated and take place again next year.
Each round, players had the opportunity to complete as many levels as possible (each requiring event-related items from the generators on the event board). After the 24 hours ran out, the rewards for playing were then transferred to the player's mainboard - this time, they could be used to upgrade a new Halloween building that was positioned near the mall.