/summon parrot ~ ~ ~ {Passengers:[{id:"husk"}]}

at net.minecraft.server.MinecraftServer.b(SourceFile:779)
	at net.minecraft.server.MinecraftServer.a(SourceFile:708)
	at dnm.a(SourceFile:128)
	at net.minecraft.server.MinecraftServer.run(SourceFile:574)
	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 aiy.a(SourceFile:54)
	at aim.a(SourceFile:94)
	at agp.cR(SourceFile:605)
	at ago.k(SourceFile:2031)
	at agp.k(SourceFile:474)
	at ape.k(SourceFile:36)
	at apw.k(SourceFile:269)
	at ago.V_(SourceFile:1882)
	at agp.V_(SourceFile:285)
	at ape.V_(SourceFile:41)
	at apw.V_(SourceFile:244)
	at agf.aJ(SourceFile:1687)
	at ago.aJ(SourceFile:2172)
	at ban.a(SourceFile:1162)
	at uh.a(SourceFile:395)
	at ban.g(SourceFile:1145)
	at ban.a(SourceFile:1210)
	at uh.a(SourceFile:395)
	at ban.g(SourceFile:1145)

-- Entity being ticked --
Details:
	Entity Type: minecraft:parrot (alv)
	Entity ID: 82
	Entity Name: 鹦鹉
	Entity's Exact location: -288.49, 11.89, -217.82
	Entity's Block location: World: (-289,11,-218), Chunk: (at 15,0,6 in -19,-14; contains blocks -304,0,-224 to -289,255,-209), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Entity's Momentum: -0.00, -0.05, 0.01
	Entity's Passengers: [apa['尸壳'/83, l='1.14test flat', x=-288.49, y=12.02, z=-217.83]]
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at ban.n_(SourceFile:1027)
	at uh.n_(SourceFile:311)

-- Affected level --
Details:
	Level name: 1.14test flat
	All players: 0 total; []
	Chunk stats: ServerChunkCache: 2025
	Level seed: -7170436028850832869
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: {}
	Level spawn location: World: (-217,9,-208), Chunk: (at 7,0,0 in -14,-13; contains blocks -224,0,-208 to -209,255,-193), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 1093175 game time, 6000 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 1 (now: false), thunder time: 1 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.b(SourceFile:779)
	at net.minecraft.server.MinecraftServer.a(SourceFile:708)
	at dnm.a(SourceFile:128)
	at net.minecraft.server.MinecraftServer.run(SourceFile:574)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 18w47b
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1109364440 bytes (1057 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
	Player Count: 0 / 8; []
	Data Packs: vanilla
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.