Moon blast is only avalable during Harvest Festival.
Harvest Moon Blast can be made be mixing 20 Songpyeon, 20 Harmony Mooncakes, and 20 Longevity Mooncakes in any Chemical Combiner.
Additional Info:
This item was released on 18th September 2013. It can be bought for 20,000 gems from Harvest Pack. One comes in a pack. Blasting it creates a moon blasted world with a big moon background and random trees that were planted and fully grown. A moon mask and one of every new mooncake, including the new one, are also included. Hand scythes were taken out of the pack.