[09:57:46 ERROR]: Could not pass event EntityDeathEvent to Killstreak v1.0.0
org.bukkit.event.EventException: null
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:500) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:485) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.callEntityDeathEvent(CraftEventFactory.java:395) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityLiving.die(EntityLiving.java:1114) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityZombie.die(EntityZombie.java:429) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityLiving.damageEntity(EntityLiving.java:956) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityMonster.damageEntity(EntityMonster.java:44) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityZombie.damageEntity(EntityZombie.java:163) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.Entity.Y(Entity.java:439) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityLiving.Y(EntityLiving.java:204) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityInsentient.Y(EntityInsentient.java:186) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.Entity.B_(Entity.java:320) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityLiving.B_(EntityLiving.java:1871) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityInsentient.B_(EntityInsentient.java:246) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityMonster.B_(EntityMonster.java:28) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.EntityZombieVillager.B_(EntityZombieVillager.java:76) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.World.entityJoinedWorld(World.java:1633) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.World.h(World.java:1603) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.World.tickEntities(World.java:1437) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.WorldServer.tickEntities(WorldServer.java:665) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:817) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [spigot.jar:git-Spigot-3d850ec-f46ccd7]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_151]
Caused by: java.lang.NullPointerException
        at com.mcsaga.plugins.killstreaks.KillStreak.on(KillStreak.java:31) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_151]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_151]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot.jar:git-Spigot-3d850ec-f46ccd7]
        ... 26 more
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