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.
1 The Arch Wyvern can spawn at any time, day or night. Usually there is a 80% more chance he will spawn at night, or at the break of evening.  It spawns most commonly at altitudes above 80 meters in small worlds.