[18:24:26 ERROR]: #!#! [Skript] Severe Error:
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Something went horribly wrong with Skript.
[18:24:26 ERROR]: #!#! This issue is NOT your fault! You probably can't fix it yourself, either.
[18:24:26 ERROR]: #!#! It looks like you are using some plugin(s) that alter how Skript works (addons).
[18:24:26 ERROR]: #!#! Here is full list of them:
[18:24:26 ERROR]: #!#! skRayFall v1.9.28 (https://sk.rayfall.net/) skUtilities v0.9.2 (https://tim740.github.io/) Reqn v1.2.3
[18:24:26 ERROR]: #!#! We could not identify which of those are specially related, so this might also be Skript issue.
[18:24:26 ERROR]: #!#! You should try disabling those plugins one by one, trying to find which one causes it.
[18:24:26 ERROR]: #!#! If the error doesn't disappear even after disabling all listed plugins, it is probably Skript issue.
[18:24:26 ERROR]: #!#! In that case, you will be given instruction on how should you report it.
[18:24:26 ERROR]: #!#! On the other hand, if the error disappears when disabling some plugin, report it to author of that plugin.
[18:24:26 ERROR]: #!#! Only if the author tells you to do so, report it to Skript's issue tracker.
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Stack trace:
[18:24:26 ERROR]: #!#! ch.njol.skript.SkriptAPIException: Call to getSingle() on a non-single expression
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.lang.util.SimpleExpression.getSingle(SimpleExpression.java:61)
[18:24:26 ERROR]: #!#! at skRayFall+v1.9.28.jar//net.rayfall.eyesniper2.skrayfall.bossbar.EffSetBossBar.execute(EffSetBossBar.java:41)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.lang.Effect.run(Effect.java:50)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.lang.TriggerItem.walk(TriggerItem.java:61)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.lang.TriggerItem.walk(TriggerItem.java:89)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.lang.Trigger.execute(Trigger.java:56)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.SkriptEventHandler.check(SkriptEventHandler.java:142)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.SkriptEventHandler.access$000(SkriptEventHandler.java:53)
[18:24:26 ERROR]: #!#! at Skript-2.6.4.jar//ch.njol.skript.SkriptEventHandler$PriorityListener.lambda$new$0(SkriptEventHandler.java:71)
[18:24:26 ERROR]: #!#! at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80)
[18:24:26 ERROR]: #!#! at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70)
[18:24:26 ERROR]: #!#! at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:54)
[18:24:26 ERROR]: #!#! at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.callEvent(PaperPluginManagerImpl.java:126)
[18:24:26 ERROR]: #!#! at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:617)
[18:24:26 ERROR]: #!#! at org.bukkit.craftbukkit.v1_19_R2.event.CraftEventFactory.callEvent(CraftEventFactory.java:250)
[18:24:26 ERROR]: #!#! at org.bukkit.craftbukkit.v1_19_R2.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:1147)
[18:24:26 ERROR]: #!#! at org.bukkit.craftbukkit.v1_19_R2.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:974)
[18:24:26 ERROR]: #!#! at org.bukkit.craftbukkit.v1_19_R2.event.CraftEventFactory.handleLivingEntityDamageEvent(CraftEventFactory.java:1208)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityLiving.damageEntity0(EntityLiving.java:2222)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityLiving.a(EntityLiving.java:1429)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.monster.EntityZombie.a(EntityZombie.java:355)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.Entity.aq(Entity.java:860)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityLiving.aq(EntityLiving.java:400)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityInsentient.aq(EntityInsentient.java:334)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.Entity.l(Entity.java:807)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityLiving.l(EntityLiving.java:3055)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.EntityInsentient.l(EntityInsentient.java:427)
[18:24:26 ERROR]: #!#! at net.minecraft.world.entity.monster.EntityZombie.l(EntityZombie.java:298)
[18:24:26 ERROR]: #!#! at net.minecraft.server.level.WorldServer.a(WorldServer.java:1294)
[18:24:26 ERROR]: #!#! at net.minecraft.server.level.WorldServer.lambda$tick$6(WorldServer.java:755)
[18:24:26 ERROR]: #!#! at net.minecraft.world.level.entity.EntityTickList.a(EntityTickList.java:42)
[18:24:26 ERROR]: #!#! at net.minecraft.server.level.WorldServer.a(WorldServer.java:732)
[18:24:26 ERROR]: #!#! at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:1564)
[18:24:26 ERROR]: #!#! at net.minecraft.server.dedicated.DedicatedServer.b(DedicatedServer.java:488)
[18:24:26 ERROR]: #!#! at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1424)
[18:24:26 ERROR]: #!#! at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:1194)
[18:24:26 ERROR]: #!#! at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:321)
[18:24:26 ERROR]: #!#! at java.base/java.lang.Thread.run(Thread.java:831)
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Version Information:
[18:24:26 ERROR]: #!#! Skript: 2.6.4 (latest)
[18:24:26 ERROR]: #!#! Flavor: skriptlang-github
[18:24:26 ERROR]: #!#! Date: 17:14:25.041218900
[18:24:26 ERROR]: #!#! Bukkit: 1.19.3-R0.1-SNAPSHOT
[18:24:26 ERROR]: #!#! Minecraft: 1.19.3
[18:24:26 ERROR]: #!#! Java: 17-ea (OpenJDK 64-Bit Server VM 17-ea+17-1401)
[18:24:26 ERROR]: #!#! OS: Linux amd64 4.15.0-204-generic
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Server platform: Paper
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Current node: null
[18:24:26 ERROR]: #!#! Current item: null
[18:24:26 ERROR]: #!#! Current trigger: damage (damage) (boss_zombie.sk, line 116)
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Thread: Server thread
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! Language: english
[18:24:26 ERROR]: #!#! Link parse mode: LENIENT
[18:24:26 ERROR]: #!#!
[18:24:26 ERROR]: #!#! End of Error.
[18:24:26 ERROR]: #!#!````

on join:
    create bossbar titled "&f&lMirriCraft" and id "bossbar.%player's uuid%" for player with progress 100 with colors white
    stop