Spawning
To spawn naturally, ghasts require a solid block below them and 5×4×5 free space in order to spawn, and only spawn in the nether , in any light level.
Drops
Ghasts drop 0-2 gun powder and sometimes a ghast tear . They also drop 5 experience when killed by a player.
Ghast Fireballs
The ghast's fireball attack has a straight trajectory unaffected by gravity and a theoretically infinite range, though it will disappear after 1 minute. Fireballs do not track the player once fired, are slow, and can be deflected if the player hits them with a projectile, fishing lure or melee attack. At close range, it is one of the most powerful mob attacks in Minecraft, fourth only to the explosion of a creeper, the melee attack of an iron golem,and the explosion of a wither skull. A direct hit will deal 6 health damage from the impact, and up to 9 health, 17 health, or 25 (health × 12.5) damage from the explosion, depending on difficulty. When two ghast fireballs collide, one is deflected to a random direction while the other explodes upon impact. Blocks are also set on fire by the explosion. If a ghast is killed, any fireball launched by that ghast will disappear. A rebounded ghast fireball will instantly kill a ghast on impact, no matter how much health the Ghast has.[]
The minimum blast resistance required to absorb all blast force of the ghast's fireballs is 20.17 (about the equivalent of a cobweb).
