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.
In the Overworld, zombies spawn in groups of 4 at a light level of 7 or less. Zombies have a 5% chance to spawn as a zombie villager and a 5% chance to spawn as a baby zombie. Baby zombies have an additional 5% chance of spawning as a chicken jockey. This also applies to spawn eggs.