Five-layered sugar chests are single-tile stationary blockers that take five matches involving sugar keys to open and therefore destroy. Each matched sugar key results in a degrade. After the first degrade, it becomes a four-layered sugar chest with only a thick red jam layer covering a pink icing layer, then after the second, becomes a three-layered sugar chest with only the pink icing layer, then after the third, becomes a two-layered sugar chest with a crumbly biscuit topping, then after the fourth and final, becomes a plain sugar chest with no toppings. These blockers cannot be destroyed by anything other than matches involving the sugar key.
Here is the difficulty of destroying a five-layered sugar chest:
It is unknown if there will be more layers added to the sugar chest, but it is highly unlikely as there isn't six-layered icing yet. It is possible that the six-layered sugar chest will contain colourful sprinkles.