The debug wand causes this error and kicks the player that attempted to use it.
Funniest part, you can't even rejoin. It keeps kicking you until the network is gone or the server restarts.
[17:52:09] [Server thread/INFO]: BTC has logged in.
[17:52:11] [Netty Epoll Server IO #0/ERROR] [FML]: NetworkDispatcher exception
java.lang.IllegalArgumentException: Payload may not be larger than 1048576 bytes
at net.minecraft.network.play.server.S3FPacketCustomPayload.<init>(S3FPacketCustomPayload.jav
a:27) ~[gg.class:?]
at net.minecraftforge.fml.common.network.internal.FMLProxyPacket.toS3FPackets(FMLProxyPacket.
java:136) ~[FMLProxyPacket.class:?]
at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.write(NetworkDispatcher.
java:510) ~[NetworkDispatcher.class:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.j
ava:658) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:71
6) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext
.java:706) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext
.java:741) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:895) ~[D
efaultChannelPipeline.class:?]
at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:240) ~[AbstractChannel
.class:?]
at net.minecraft.network.NetworkManager$4.run(NetworkManager.java:249) [ek$4.class:?]
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.j
ava:380) [SingleThreadEventExecutor.class:?]
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:268) [EpollEventLoop.class:?
]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:11
6) [SingleThreadEventExecutor$2.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
[17:52:11] [Server thread/INFO]: BTC lost connection: Internal Exception: java.lang.IllegalArgumentEx
ception: Payload may not be larger than 1048576 bytes
[17:52:11] [Server thread/INFO]: BTC has disconnected.
The debug wand causes this error and kicks the player that attempted to use it. Funniest part, you can't even rejoin. It keeps kicking you until the network is gone or the server restarts.