When a player shoots himself with a bow he will be damaged by his own thorns enchantment.
- Use the following command and equip the chestplate
- Shoot yourself
→ Your chestplate will break and you will die because of the thorns damage
The following is based on a decompiled version of Minecraft 1.10 using MCP 9.30.
This could probably be tested in the methods net.minecraft.enchantment.EnchantmentHelper.applyThornEnchantments(EntityLivingBase, Entity) (better?) or net.minecraft.enchantment.EnchantmentThorns.onUserHurt(EntityLivingBase, Entity, int).