Each Monster occupies a certain number of Beds, which are managed in the Castle. The number of Beds required is specific to each Monster and can be found in the Monster’s Info section.

If the Monster you are trying to place requires more Beds than the Castle has available, you can add more Beds by upgrading the Castle, or you can sell an existing Monster to make room for the new Monster.

You can also purchase a second Castle for Diamonds or buy a Hotel for Coins!