Bug by falling out of the world in the end

Bug by falling out of the world in the end in creative.

---- Minecraft Crash Report ----
// I let you down. Sorry

Time: 6-8-15 13:34
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
at vn.k(SourceFile:69)
at vn.j(SourceFile:65)
at vn.c(SourceFile:30)
at va.m(SourceFile:231)
at qj.t_(SourceFile:1404)
at qk.t_(SourceFile:228)
at afk.a(SourceFile:1407)
at lg.a(SourceFile:599)
at afk.g(SourceFile:1385)
at afk.j(SourceFile:1278)
at lg.j(SourceFile:480)
at net.minecraft.server.MinecraftServer.B(SourceFile:607)
at net.minecraft.server.MinecraftServer.A(SourceFile:535)
at btd.A(SourceFile:152)
at net.minecraft.server.MinecraftServer.run(SourceFile:451)
at java.lang.Thread.run(Thread.java:695)

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

– Head –
Stacktrace:
at vn.k(SourceFile:69)
at vn.j(SourceFile:65)
at vn.c(SourceFile:30)
at va.m(SourceFile:231)
at qj.t_(SourceFile:1404)
at qk.t_(SourceFile:228)
at afk.a(SourceFile:1407)
at lg.a(SourceFile:599)
at afk.g(SourceFile:1385)

– Entity being ticked –
Details:
Entity Type: EnderDragon (va)
Entity ID: 39951
System: Mac OS X (x86_64) version 10.9.5
Java Version: 1.6.0_65, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 314770064 bytes (300 MB) / 570880000 bytes (544 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [lh['AlexanderMea'/165, l='NEW YORKING', x=106,36, y=-256,71, z=-0,89]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.