My mod is crashing the game (SOLVED)

Everytime i open a world in minecraft with my mod the game crashes.

This is the crash report:

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 4/24/19 7:01 PM
Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
    at mod.mcreator.mcreator_herobrineOnInitialMobSpawn.executeProcedure(mcreator_herobrineOnInitialMobSpawn.java:24)
    at mod.mcreator.mcreator_herobrine$Entityherobrine.func_180482_a(mcreator_herobrine.java:160)
    at net.minecraft.world.WorldEntitySpawner.func_77191_a(WorldEntitySpawner.java:299)
    at net.minecraft.world.gen.ChunkGeneratorOverworld.func_185931_b(ChunkGeneratorOverworld.java:466)
    at net.minecraft.world.chunk.Chunk.func_186034_a(Chunk.java:1019)
    at net.minecraft.world.chunk.Chunk.func_186030_a(Chunk.java:999)
    at net.minecraft.world.gen.ChunkProviderServer.func_186025_d(ChunkProviderServer.java:157)
    at net.minecraft.server.MinecraftServer.func_71222_d(MinecraftServer.java:344)
    at net.minecraft.server.integrated.IntegratedServer.func_71247_a(IntegratedServer.java:142)
    at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:156)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:486)
    at java.lang.Thread.run(Unknown Source)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
    Minecraft Version: 1.12.2
    Operating System: Windows 8 (amd64) version 6.2
    Java Version: 1.8.0_191, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 171275912 bytes (163 MB) / 378941440 bytes (361 MB) up to 1037959168 bytes (989 MB)
    JVM Flags: 8 total; -XX:+UseConcMarkSweepGC -XX:-UseAdaptiveSizePolicy -XX:+CMSParallelRemarkEnabled -XX:+ParallelRefProcEnabled -XX:+CMSClassUnloadingEnabled -XX:+UseCMSInitiatingOccupancyOnly -Xmx1024M -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
    IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
    FML: MCP 9.42 Powered by Forge 14.23.5.2768 5 mods loaded, 5 mods active
    States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored

    | State   | ID                  | Version      | Source                        | Signature                                |
    |:------- |:------------------- |:------------ |:----------------------------- |:---------------------------------------- |
    | UCHIJAA | minecraft           | 1.12.2       | minecraft.jar                 | None                                     |
    | UCHIJAA | mcp                 | 9.42         | minecraft.jar                 | None                                     |
    | UCHIJAA | FML                 | 8.0.99.99    | forge-1.12.2-14.23.5.2768.jar | e3c3d50c7c986df74c645c0ac54639741c90a557 |
    | UCHIJAA | forge               | 14.23.5.2768 | forge-1.12.2-14.23.5.2768.jar | e3c3d50c7c986df74c645c0ac54639741c90a557 |
    | UCHIJAA | herobrine_nightmare | 1.12.2       | Herobrine_Nightmare.jar       | None                                     |

    Loaded coremods (and transformers): 
    GL info: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
    Profiler Position: N/A (disabled)
    Player Count: 0 / 8; []
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'fml,forge'

pls help  :(