The Grass Block was added on 10/1/18. It came in packs of three. Like Wood and the Sand Block, this block is weak and is mainly used for decoration or flooring. Its texture is that of grass in ROBLOX Studio. It was added back to the shop on 7/17/19.
Grass Blocks could be obtained from the code "Christmas tree" (Expired) ,"Fancy Dino" (Expired) or "The Decoding Of The Boat"(Valid), before moving into the shop where the player could buy 3 for 50 Gold for a limited time. It can be used with the 'infinite path' glitch to 'remove the water' on the map. When the player walks on this block, it makes the same sound as the building area.
Grass blocks have appeared in the shop in packs of 50 as of the shop update. Plus, it is expected to appear again sometimes when the shop switches to new blocks.