Dark Glass (Extra Utilities)

Dark Glass is a block added by Extra Utilities. It has the unique property of being completely transparent and opaque at the same time. Any light source hitting the block from the outside will be blocked, causing an area covered with Dark Glass to be completely dark. If the covered area is hit with light from the inside, the area will be lit normally.

Applications
Using the Dark Glass in combination with Cursed Earth can allow for mob farms.