Parallel drainage pattern. A parallel drainage system is a pattern of rivers caused by steep slopes with some relief. Because of the steep slopes, the streams are swift and straight, with very few tributaries, and all flow in the same direction.
1 In Creative, the player can use spawn eggs to spawn most mobs. 2  When mobs are spawned this way, all normal spawning requirements, such as light level and block type, are ignored. 3  Any entity can be spawned using the /summon command.
There is only a 10% chance of spawning slimes in any game chunk. This makes slimes one of the rarest mobs in the game. They can spawn in well lit areas, so it is best to light a slime farm well to decrease the chance of other mobs spawning there.