NetherResident

I believe that movement is done through the server, then rendered through the client. Not sure if that was the question. I think you may need to use a packet to handle the spawning, anyways check if the entity is spawned correctly by adding this code to the update method: if(!this.worldObj.isRemote){ System.out.println("[server] Ticked on server."); } If you see this message in the console, then you for sure will know that the entity is spawned on the server side.

Are you sure you are spawning the new projectile on the server? Check this by implementing the follow check: if(!par2World.isRemote){ EntityHook hook = new EntityHook(par2World, par3EntityPlayer); par2World.spawnEntityInWorld(hook); }