Creature spawner

A Creature spawner is a destructible entity that continuously spawns hostile creatures. These come in various types, each having their own unique enemies they spawn. They can usually be identified by a dark purple or green smoke that floats above them.
== List of Creature Spawners ==
* Greydwarf nest
** Greydwarf
** Greydwarf shaman
** Greydwarf brute
* Evil bone pile
** Skeleton
* Body pile
** Draugr
** Draugr elite
== Spawning Mechanics ==
Below is the step-by-step process for spawning. The exact numerical value depends on the type of spawner.
*Become active if there is a player within 20 or 60 meters.
*Try to spawn every 6 or 12 seconds.
*Skip spawning if there is 2 or 3 enemies within 20 meters. Only counts enemies that the spawner can spawn.
*Skip spawning if there is 100 enemies within 1000 meters. Only counts enemies that the spawner can spawn.
*Try 10 times to find a valid spawn point within 2.28, 3 or 4 meters.
*Valid spawnpoint requires ground. Greydwarf nest also requires that the ground is not covered.
*Randomly select the spawned enemy type (chances depend on the weight).
*Randomly level up the spawned enemy (15% chance per level up), up to 2 stars.
For example Greydwarf nest has 5 weight for Greydwarf, 1 weight for Brute and 1 weight for Shaman. These end up as 72% chance for Greydwarf, 14% chance for Brute and 14% chance for Shaman.
Type 	Spawn weights 	Active distance	Max near	Interval	Spawn radius	Only ground
Evil bone pile	Skeleton 	20 m 	2 	6 s 	2.28 m 	
Greydwarf nest	Greydwarf 5, Brute 1, Shaman 1	60 m 	3 	12 s 	4 m 	Yes
Body pile 	Draugr 4, Elite 1, Ranged 2 	20 m 	2 	6 s 	3 m 	
*Spawn weights: Enemy types to spawn and their relative spawn weight.
*Active distance: Distance to activate the spawner.
*Max near: Maximum amount of units within 20 meters.
*Interval: How many seconds per spawn.
*Spawn radius: Spawn location max distance from the spawner.
*Only ground: Requires uncovered ground. If you build roof then the spawning fails (floor should work too).
== Notes ==
*Creature spawners are not suppressed by Player base structures unlike spawn zones and spawn points.
*Fire geysers are not a creature spawner, as they are not destructible and their spawning works a little differently. They are a spawn point.