So basically, the mob is spawned in by onRightClick in the ItemMag.class, it is suppose to follow the player and be like directly behind the player and by its shoulder at all times but problem 1. Dont know how to set position for it, it usually stays up high, because I modeled it in the Ideal location so really its just a matter of keeping close behind the player. problem 2. the Mob wont follow the player at all, I think its the ItemMag.class error. problem 3. is onLeftClick doesnt despawn the mob, when it should. I want a player to only be able to spawn 1 of the entity. Here are  my classes.

ItemMag.class

package com.phantasyrealms.item;

import com.phantasyrealms.entity.EntityMag;
import com.phantasyrealms.lib.Strings;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ChatComponentTranslation;
import net.minecraft.world.World;


public class ItemMag extends Item{

 EntityMag par1;

 public ItemStack onItemRightClick(ItemStack itemstack, World world, EntityPlayer player){
  if(par1 == null){
        par1 = new EntityMag(world);
        par1.setPosition(player.posX, player.posY+1,player.posZ-2);
        par1.func_152115_b(player.getUniqueID().toString());
        world.spawnEntityInWorld(par1);
        player.inventory.addItemStackToInventory(new ItemStack(PhantasyRealmsItems.mag));
        --itemstack.stackSize;
  }
  else{
  player.addChatComponentMessage(new ChatComponentTranslation ("Already Have one!"));
 }
  return null;
 }


  public ItemStack onItemLeftClick(ItemStack itemstack, World world, EntityPlayer player){
   par1.func_152115_b(player.getUniqueID().toString());
   world.removeEntity(par1);
   player.addChatComponentMessage(new ChatComponentTranslation ("RETURN!"));
   player.inventory.addItemStackToInventory(new ItemStack(PhantasyRealmsItems.mag));
   return null;
  }
}

 

EntityMag.class

package com.phantasyrealms.entity;

import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityAgeable;
import net.minecraft.entity.EntityLiving;
import net.minecraft.entity.EnumCreatureAttribute;
import net.minecraft.entity.SharedMonsterAttributes;
import net.minecraft.entity.ai.EntityAIAttackOnCollide;
import net.minecraft.entity.ai.EntityAIBeg;
import net.minecraft.entity.ai.EntityAIFollowOwner;
import net.minecraft.entity.ai.EntityAIHurtByTarget;
import net.minecraft.entity.ai.EntityAILeapAtTarget;
import net.minecraft.entity.ai.EntityAILookIdle;
import net.minecraft.entity.ai.EntityAIMate;
import net.minecraft.entity.ai.EntityAINearestAttackableTarget;
import net.minecraft.entity.ai.EntityAIOwnerHurtByTarget;
import net.minecraft.entity.ai.EntityAIOwnerHurtTarget;
import net.minecraft.entity.ai.EntityAISwimming;
import net.minecraft.entity.ai.EntityAITargetNonTamed;
import net.minecraft.entity.ai.EntityAIWander;
import net.minecraft.entity.ai.EntityAIWatchClosest;
import net.minecraft.entity.monster.IMob;
import net.minecraft.entity.passive.EntitySheep;
import net.minecraft.entity.passive.EntityTameable;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.DamageSource;
import net.minecraft.world.World;

public class EntityMag extends EntityTameable
{


public EntityMag(World world)
{
super(world);
this.getNavigator().setAvoidsWater(true);
this.tasks.addTask(1, new EntityAISwimming(this));
this.tasks.addTask(3, new EntityAILeapAtTarget(this, 0.4F));
this.tasks.addTask(4, new EntityAIAttackOnCollide(this, 1.0D, true));
this.tasks.addTask(5, new EntityAIFollowOwner(this, 1.0D, 10.0F, 2.0F));
this.tasks.addTask(7, new EntityAIWander(this, 1.0D));
this.tasks.addTask(9, new EntityAIWatchClosest(this, EntityPlayer.class, 8.0F));
this.tasks.addTask(9, new EntityAILookIdle(this));
this.targetTasks.addTask(1, new EntityAIOwnerHurtByTarget(this));
this.targetTasks.addTask(2, new EntityAIOwnerHurtTarget(this));
this.targetTasks.addTask(4, new EntityAITargetNonTamed(this, EntitySheep.class, 200, false));
this.setSize(0.9F, 0.9F);

}

protected void applyEntityAttributes(){
super.applyEntityAttributes();
this.getEntityAttribute(SharedMonsterAttributes.movementSpeed).setBaseValue(0.2);
this.getEntityAttribute(SharedMonsterAttributes.maxHealth).setBaseValue(20.0D);
}

public boolean attackEntityAsMob(Entity par1Entity)
{
int i = 5;
return par1Entity.attackEntityFrom(DamageSource.causeMobDamage(this), 5.0F);
}

protected boolean isAIEnabled()
{
return true;
}


public void onDeath(DamageSource par1DamageSource)
{
super.onDeath(par1DamageSource);

}

public EnumCreatureAttribute getCreatureAttribute()
{
return EnumCreatureAttribute.UNDEFINED;
}

public boolean interact(EntityPlayer par1EntityPlayer){
this.func_152115_b(par1EntityPlayer.getUniqueID().toString());
return true;
}

protected boolean canDespawn()
{
return false;
}

protected void dropFewItems(boolean par1, int par2)
{

}

public EntityAgeable createChild(EntityAgeable entityageable)
{
return null;
}
}

You cant store data in your item class you need to use NBT for that.

You cant store data in your item class you need to use NBT for that.

How would I do this, I have never touched NBT methods and usage before.