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.
Slimes spawn in random underground chunks below Y=39 at any light level, and can also spawn in Swamp Biomes at night depending on the phase of the Moon. They spawn more frequently during a full moon, and never spawn during a new moon.