Crash logs are attached.

MC 1.11.2
Forge 13.20.0.2252
Optifine 1.11.2 HD U B8 PRE

[spoiler]java.lang.NoSuchMethodError: atomicstryker.stalkercreepers.common.EntityAIHelperStalker.isSeenByTarget(Lnet/minecraft/entity/EntityLivingBase;)Z
at net.minecraft.entity.ai.EntityAICreeperSwell.func_75250_a(SourceFile:19)
at net.minecraft.entity.ai.EntityAITasks.func_75774_a(SourceFile:94)
at net.minecraft.entity.EntityLiving.func_70626_be(EntityLiving.java:895)
at net.minecraft.entity.EntityLivingBase.func_70636_d(EntityLivingBase.java:2255)
at net.minecraft.entity.EntityLiving.func_70636_d(EntityLiving.java:680)
at net.minecraft.entity.monster.EntityMob.func_70636_d(SourceFile:41)
at net.minecraft.entity.EntityLivingBase.func_70071_h_(EntityLivingBase.java:2085)
at net.minecraft.entity.EntityLiving.func_70071_h_(EntityLiving.java:384)
at net.minecraft.entity.monster.EntityMob.func_70071_h_(SourceFile:46)
at net.minecraft.entity.monster.EntityCreeper.func_70071_h_(SourceFile:161)
at net.minecraft.world.World.func_72866_a(World.java:1961)
at net.minecraft.world.WorldServer.func_72866_a(WorldServer.java:840)
at net.minecraft.world.World.func_72870_g(World.java:1931)
at net.minecraft.world.World.func_72939_s(World.java:1747)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:621)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:720)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:624)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:240)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:482)
at java.lang.Thread.run(Thread.java:745)

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

-- Head --
Thread: Server thread
Stacktrace:
at net.minecraft.entity.ai.EntityAICreeperSwell.func_75250_a(SourceFile:19)
at net.minecraft.entity.ai.EntityAITasks.func_75774_a(SourceFile:94)
at net.minecraft.entity.EntityLiving.func_70626_be(EntityLiving.java:895)
at net.minecraft.entity.EntityLivingBase.func_70636_d(EntityLivingBase.java:2255)
at net.minecraft.entity.EntityLiving.func_70636_d(EntityLiving.java:680)
at net.minecraft.entity.monster.EntityMob.func_70636_d(SourceFile:41)
at net.minecraft.entity.EntityLivingBase.func_70071_h_(EntityLivingBase.java:2085)
at net.minecraft.entity.EntityLiving.func_70071_h_(EntityLiving.java:384)
at net.minecraft.entity.monster.EntityMob.func_70071_h_(SourceFile:46)
at net.minecraft.entity.monster.EntityCreeper.func_70071_h_(SourceFile:161)
at net.minecraft.world.World.func_72866_a(World.java:1961)
at net.minecraft.world.WorldServer.func_72866_a(WorldServer.java:840)
at net.minecraft.world.World.func_72870_g(World.java:1931)

-- Entity being ticked --
Details:
Entity Type: minecraft:creeper (net.minecraft.entity.monster.EntityCreeper)
Entity ID: 239
Entity Name: Creeper
Entity's Exact location: 38.27, 51.00, 258.50
Entity's Block location: World: (38,51,258), Chunk: (at 6,3,2 in 2,16; contains blocks 32,0,256 to 47,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Entity's Momentum: 0.00, -0.08, 0.00
Entity's Passengers: []
Entity's Vehicle: ERROR NullPointerException: null
Stacktrace:
at net.minecraft.world.World.func_72939_s(World.java:1747)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:621)

-- Affected level --
Details:
Level name: Test
All players: 1 total; [EntityPlayerMP['sprinkles'/420, l='Test', x=39.99, y=51.00, z=259.83]]
Chunk stats: ServerChunkCache: 625 Drop: 0
Level seed: 7661900886522797728
Level generator: ID 06 - BIOMESOP, ver 0. Features enabled: true
Level generator options:
Level spawn location: World: (56,64,236), Chunk: (at 8,4,12 in 3,14; contains blocks 48,0,224 to 63,255,239), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 17364 game time, 17364 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 31190 (now: false), thunder time: 26287 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:720)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:624)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:240)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:482)
at java.lang.Thread.run(Thread.java:745)[/spoiler]

crash-2017-02-26_14.18.06-server.txt

fml-client-latest.txt

4b77919

this should fix that, please check

(i pushed updated files to my website and curse, also github.io)

Thanks for the update, AtomicStryker!

I'll check it out this afternoon with my daughter :).

FYI, your Curse didn't update. Last update Jan 7, 2016.

GITHUB.IO = 10.6KB
Curse = 8.67KB
AtomicStryker.net = ?? (can't get through adfly at work :P)