[20:18:04] [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.server.v1_8_R3.ReportedException: Exception ticking world
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:784) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]
Caused by: java.lang.IllegalArgumentException
	at net.minecraft.server.v1_8_R3.WeightedRandom.a(SourceFile:17) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.WeightedRandom.a(SourceFile:35) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EnchantmentManager.b(EnchantmentManager.java:342) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EnchantmentManager.a(EnchantmentManager.java:264) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EntityInsentient.b(EntityInsentient.java:730) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EntityZombie.prepare(EntityZombie.java:415) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.SpawnerCreature.a(SpawnerCreature.java:179) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.WorldServer.doTick(WorldServer.java:227) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:773) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	... 4 more
[20:18:04] [Server thread/ERROR]: 	Cause of unexpected exception was
java.lang.IllegalArgumentException
	at net.minecraft.server.v1_8_R3.WeightedRandom.a(SourceFile:17) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.WeightedRandom.a(SourceFile:35) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EnchantmentManager.b(EnchantmentManager.java:342) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EnchantmentManager.a(EnchantmentManager.java:264) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EntityInsentient.b(EntityInsentient.java:730) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.EntityZombie.prepare(EntityZombie.java:415) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.SpawnerCreature.a(SpawnerCreature.java:179) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.WorldServer.doTick(WorldServer.java:227) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:773) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) ~[spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot-1.8.7.jar:git-Spigot-f928e7a-e91aed8]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]