private static int getFirstEmptySlot(InventoryItem[] targetInventory)
    {
        //If it finds nothing, return -1
        int index = -1;
        //scan the targetInventory, looking for EmptyItem's
        for(int i = 0; i<targetInventory.length; i++)
        {
           //it if finds one, set the index as that and break.
            if(targetInventory[i].equals(Parasite.items.EmptyItem))
           {
               index = i;
               break;
           }
        }
        //return the index, be it a real index or -1
        return index;
    }