The Bubblegum Block is a building material crafted from Stone Blocks and Orichalcum Ore. When placed, it resembles stone blocks coated with bubblegum. It is essentially the Orichalcum Ore's equivalent of a Brick.
Due to the fact that Orichalcum Ore is required to craft it, in a world where Mythril Ore is generated, the only way to obtain the Bubblegum Block is through fishing.