My idea is to make mobs that don't spawn in survival/wilderness to Essalonia.
List:
Wither Skeletons
Blazes (taking away their flame throwing griefing or setting the flame temporary)
Water Guardians (exept for that big one that gives you slow mining)
Siverfish (bringing in some of these into the stones in the ground)
Havent before seen on massive (but its all 1.12 now so might as well bring these!
Stray and Hush for specific biomes
Evoker
Vindicator
illusioner
List:
Wither Skeletons
Blazes (taking away their flame throwing griefing or setting the flame temporary)
Water Guardians (exept for that big one that gives you slow mining)
Siverfish (bringing in some of these into the stones in the ground)
Havent before seen on massive (but its all 1.12 now so might as well bring these!
Stray and Hush for specific biomes
Evoker
Vindicator
illusioner