Firstly, you will need to craft a Ghast Shrine, with Obsidian on the top row, a Ghast Tear in the middle, and Netherbrick (the block or the item) in every other place. Then, right click to activate it. You can also activate it using Redstone. Once activated, it cannot be broken. It will continually flash from about five seconds to two minutes or so, before exploding, and summoning the Ghast Queen. The Ghast Queen has forty HP (compared to a regular Ghast's 10 HP) and will rapidly fire fireballs straight at the player. If defeated, it will drop all regular Ghast drops as well as one Ghast Egg. When a Ghast Egg is crafted in the shape of a shovel with Blaze Rods instead of sticks (you could also craft it diagonally) you will get an Inferno Staff, which when right clicked shoots fireballs at your target.