I placed an enderdragon head and i put it back in the creative inventory and i wanted i back a little bit later and i clicked on it with the scroll wheel on the mouse and first the game frozen and a sec later the game was gone and i ended up with this:

---- Minecraft Crash Report ----
// Don't do that.

Time: 15.08.15 12:55
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
at acj.a(SourceFile:401)
at yp.k(SourceFile:282)
at yq.m(SourceFile:404)
at biz.m(SourceFile:708)
at rd.r_(SourceFile:1436)
at yq.r_(SourceFile:229)
at biz.r_(SourceFile:114)
at agh.a(SourceFile:1414)
at agh.g(SourceFile:1392)
at agh.j(SourceFile:1285)
at ayy.s(SourceFile:1845)
at ayy.au(SourceFile:879)
at ayy.a(SourceFile:328)
at net.minecraft.client.main.Main.main(SourceFile:125)

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

– Head –
Stacktrace:
at acj.a(SourceFile:401)
at yp.k(SourceFile:282)
at yq.m(SourceFile:404)
at biz.m(SourceFile:708)
at rd.r_(SourceFile:1436)
at yq.r_(SourceFile:229)
at biz.r_(SourceFile:114)
at agh.a(SourceFile:1414)
at agh.g(SourceFile:1392)

– Entity being ticked –
Details:
Entity Type: null (biz)
Entity ID: 0
Entity Name: owirren
Entity's Exact location: -406,24, 61,11, 468,31
Entity's Block location: -407,00,61,00,468,00 - World: (-407,61,468), Chunk: (at 9,3,4 in -26,29; contains blocks -416,0,464 to -401,255,479), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Entity's Momentum: 0,01, 0,00, 0,00
Entity's Rider: ~_ERROR~ NullPointerException: null
Entity's Vehicle: ~_ERROR~ NullPointerException: null
Stacktrace:
at agh.j(SourceFile:1285)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [biz['owirren'/0, l='MpServer', x=-406,24, y=61,11, z=468,31]]
Chunk stats: MultiplayerChunkCache: 289, 289
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options:
Level spawn location: -405,00,4,00,469,00 - World: (-405,4,469), Chunk: (at 11,0,5 in -26,29; contains blocks -416,0,464 to -401,255,479), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 28109 game time, 14597 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 1 total; [biz['owirren'/0, l='MpServer', x=-406,24, y=61,11, z=468,31]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bhb.a(SourceFile:314)
at ayy.b(SourceFile:2297)
at ayy.a(SourceFile:337)
at net.minecraft.client.main.Main.main(SourceFile:125)

– System Details –
Details:
Minecraft Version: 15w33c
Operating System: Windows 8.1 (amd64) version 6.3
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 110655880 bytes (105 MB) / 307617792 bytes (293 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 15w33c
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics 4600 GL version 4.2.0 - Build 10.18.10.3304, Intel
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: English (US)
Profiler Position: N/A (disabled)
CPU: 8x Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz