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 have the same mob cap as other mobs, so they won't spawn very frequently if there are a lot of unlit caves around. To get good rates, light up all caves at least in a 30 block radius (150 blocks for perfect rates), and make sure the room itself is lit up. Slimes spawn in lit areas underground, and that will keep the other mobs from spawning. Another tip: create multiple levels in the slime chunk, and you'll get tons more slimes!