A bug kicking me not only from the server but closing Minecraft and taking me back to the launcher

In SkyBlock I keep getting disconnected from Minecraft and i get this exact message

Could not cast pig to player | X |

We're sorry,but it seems there was an issue while communicating with the server.

Please let the server owners know of this error!

Technical description: Could not cast entity pig to entity player
| OK |

 

Did you use the /d command?
I've heard about the crashes caused by the command... Im not sure if people crash because they use the command, or because other people use it.

The higher staff memebers are working on it, dont worry.