org.bukkit.event.EventException: null
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:500) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:485) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.callEntityDeathEvent(CraftEventFactory.java:395) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityLiving.die(EntityLiving.java:1116) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityZombie.die(EntityZombie.java:429) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityLiving.damageEntity(EntityLiving.java:956) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityMonster.damageEntity(EntityMonster.java:44) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityZombie.damageEntity(EntityZombie.java:163) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityArrow.a(EntityArrow.java:286) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityArrow.B_(EntityArrow.java:194) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.EntityTippedArrow.B_(EntityTippedArrow.java:86) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.World.entityJoinedWorld(World.java:1631) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.World.h(World.java:1601) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.World.tickEntities(World.java:1435) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.WorldServer.tickEntities(WorldServer.java:668) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:817) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]
Caused by: java.lang.NullPointerException
at tk.ddarkinferno.ablax.havenheads.DropHeads.mobDeath(DropHeads.java:32) ~[?:?]
at sun.reflect.GeneratedMethodAccessor213.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_171]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_171]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigotmc-1.12.2-R0.1.jar:git-Spigot-2086bb0-1988d7f]
... 21 more