http://ift.tt/2dSSBmR

The issue with Shulker Shells/Boxes in 1.11 is that on large servers End Cities will be wiped clean of Shulkers. I propose a solution that, I feel, has a vanilla Minecraft vibe to it.

With this command block setup, Endermites can be turned into Shulkers. But shooting an Endermite that is under the effect of a Lingering Potion of Regeneration with a Spectral Arrow it will undergo "metamorphosis" and turn into a Shulker.

I feel that a larva type mob, such as the Endermite, would turn into a chrysalis type mob, such as the Shulker.

I am no genius with command block, so if you have a way to compact what I have made please do so! Just be sure to give credit, of course. :-]

Commands

1 – /testfor @e[type=endermite] {ActiveEffects:[{Id:24b}]}

2 – /testfor @e[type=endermite] {ActiveEffects:[{Id:10b}]}

3 – /execute @e[type=area_effect_cloud] ~ ~ ~ /scoreboard players tag @e[type=endermite,r=3,c=1,tag=!shell] add shell

4 – /execute @e[tag=shell,type=endermite] ~ ~ ~ /summon shulker ~ ~ ~ {Color:10}

5 – /tp @e[tag=shell,type=endermite] ~ -300 ~