Crash: Command "Summon SmallFireball" on Mobs!

-I Write this command in command block :

/summon SmallFireball ~ ~10 ~5 {direction:[0.0,-1.0,0.0],Motion:[0.0,-1.0,0.0]}

• I activate with redstone!

• The Smallfireball summoned, hit a Creeper or Skeleton (or anyone of mobs)!

• Then minecraft crash with a big freeze.

• It's impossible to go back in my game part.

My crash report :

---- Minecraft Crash Report ----
// My bad.

Time: 22/08/14 12:51
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at apf.b(SourceFile:222)
	at wv.a(SourceFile:1975)
	at ahn.a(SourceFile:35)
	at ahj.s_(SourceFile:148)
	at aqs.a(SourceFile:1406)
	at qt.a(SourceFile:601)
	at aqs.g(SourceFile:1384)
	at aqs.i(SourceFile:1277)
	at qt.i(SourceFile:479)
	at net.minecraft.server.MinecraftServer.z(SourceFile:607)
	at net.minecraft.server.MinecraftServer.y(SourceFile:531)
	at cyf.y(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:447)
	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 --
Stacktrace:
	at apf.b(SourceFile:222)
	at wv.a(SourceFile:1975)
	at ahn.a(SourceFile:35)
	at ahj.s_(SourceFile:148)
	at aqs.a(SourceFile:1406)
	at qt.a(SourceFile:601)
	at aqs.g(SourceFile:1384)

-- Entity being ticked --
Details:
	Entity Type: SmallFireball (ahn)
	Entity ID: 22387
	Entity Name: Small Fireball
	Entity's Exact location: -286,50, 56,25, 527,50
	Entity's Block location: -287,00,56,00,527,00 - World: (-287,56,527), Chunk: (at 1,3,15 in -18,32; contains blocks -288,0,512 to -273,255,527), Region: (-1,1; contains chunks -32,32 to -1,63, blocks -512,0,512 to -1,255,1023)
	Entity's Momentum: 0,00, -0,49, 0,00
	Entity's Rider: ~~ERROR~~ NullPointerException: null
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at aqs.i(SourceFile:1277)
	at qt.i(SourceFile:479)

-- Affected level --
Details:
	Level name: Snapshot 1.8
	All players: 1 total; [qw['Piccomaster'/25, l='Snapshot 1.8', x=-294,21, y=57,71, z=529,34]]
	Chunk stats: ServerChunkCache: 1092 Drop: 0
	Level seed: -6751089128293254833
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: 3;minecraft:bedrock,3*minecraft:stone,52*minecraft:sandstone;2;stronghold,biome_1,village,decoration,dungeon,mineshaft
	Level spawn location: -340,00,4,00,465,00 - World: (-340,4,465), Chunk: (at 12,0,1 in -22,29; contains blocks -352,0,464 to -337,255,479), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 1824058 game time, 174138 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 52868 (now: false), thunder time: 69218 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.z(SourceFile:607)
	at net.minecraft.server.MinecraftServer.y(SourceFile:531)
	at cyf.y(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:447)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 1.8-pre1
	Operating System: Mac OS X (x86_64) version 10.9.4
	Java Version: 1.7.0_67, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 284849264 bytes (271 MB) / 1060372480 bytes (1011 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: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [qw['Piccomaster'/25, l='Snapshot 1.8', x=-294,21, y=57,71, z=529,34]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.