SpigotVIP ☛ Boss ~ Unbelievable Custom Monsters [1.8.9 - 1.13.2] v4.9.7

Full bug

[23:28:54 WARN]: Exception in thread "Craft Scheduler Thread - 13"
[23:28:54 WARN]: org.apache.commons.lang.UnhandledException: Plugin Boss v3.4.19 generated an exception while executing task 189
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:56)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Nodes must be provided.
at org.yaml.snakeyaml.nodes.NodeTuple.<init>(NodeTuple.java:28)
at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:163)
at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:304)
at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:94)
at org.yaml.snakeyaml.representer.BaseRepresenter.represent(BaseRepresenter.java:64)
at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:242)
at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:206)
at org.yaml.snakeyaml.Yaml.dump(Yaml.java:181)
at org.bukkit.configuration.file.YamlConfiguration.saveToString(YamlConfiguration.java:40)
at org.bukkit.configuration.file.FileConfiguration.save(FileConfiguration.java:103)
at org.mineacademy.boss.double. .a.const(SourceFile:1625)
at org.mineacademy.boss.double. .d.super(SourceFile:421)
at org.mineacademy.boss.double. .d.native(SourceFile:1185)
at org.mineacademy.boss.double. .az.do(SourceFile:127)
at org.mineacademy.boss.double. .az.if(SourceFile:70)
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71)
at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
... 3 more