Mod is simple. If creeper and player gets close, another every living entities run away from creeper.
Another creeper gets close to player dont run away from first creeper anymore
If you are a mod developer, Can use "creeperfear" tag for same effect your entity
1.1 version use new mcreator find pack AI system. creatures now run away more realistic
Just make this in mcreator
Test a another mod compatibility (old version fear system):
The Creeper Fear Team
