Respawning Shulkers

Requires the library mod Collective.

     This mod is part of The Vanilla Experience.
Respawning Shulkers is a mod which makes the process of farming shulker boxes sustainable. Shulkers can quickly become difficult to find in a world, because of the usefulness of shulker boxes. Normally you'd have to find new shulker spawns after your first farming trip. With this mod, you'll be able to stay in the same place and farm shulker shells infinitely. Shulkers can still teleport, leaving it balanced.

By default a shulker will respawn in its death location after 60 seconds, although this can be changed in the config. When a server (or singleplayer world) shuts down, all pending shulker spawns will process immediately.

Shulkers that originate from a mob spawner by default won't respawn.

Configurable:
timeInTicksToRespawn (default = 1200, min 1, max 72000): The amount of time in ticks it takes for a shulker to respawn after it died. 20 ticks = 1 second. By default 60 seconds.
shulkersFromSpawnersDoNotRespawn (default = true): If enabled, shulkers which spawn from (modded) spawners will not be respawned after a death.

Some GIFs:
With the respawn timer set low for the example.

The two shulkers at the entrance respawning:

A shulker teleporting after being damaged. The shulker will respawn at its death location, not at the initial spawn. This makes farming them still somewhat difficult but balanced: