The filled honeycomb block can be found in hives that generate in the Nether, and can also be crafted with 4 filled honeycomb. When broken it drops filled honeycomb, breaking it with a pickaxe causes it not to drop. Axes break this block the quickest.
It can be used as a furnace fuel and smelts 1 1/2 items. It can also be used as a decoration block.