In order to be able to get this event, please make sure to update your game after 12 September 2020. This is a seasonal event that will be removed from the game after it ends and will not come back.
In order to be able to participate in the Witch Cauldron, you need to have finished renovating area 2 (Episode 4).
In order to participate in the Booster Crates event you need to be at level 33 or above.
During the Witch Cauldron event, each time you explode a Blaster you'll earn a Pumpkin. As you earn enough Pumpkins, you'll get a chance to open a Cauldron and earn a surprise exclusive Halloween decoration for area 2 (reception)! You'll get to keep the items you earn from this event after the event ends, and you can find them among the other decoration selections by long tapping on an item on the area.
During Booster Crates event, as you level up you'll fill a bar. Once the bar is full, you'll get to open a Booster Crate and get a surprise Booster! You can save your Boosters to use after the event ends, too.