on_place = function(itemstack, placer, pointed_thing)


      local itemstack, pos = minetest.item_place(itemstack, placer, pointed_thing)
      local itemstack_meta = itemstack:get_meta()
      local node_meta = minetest.get_meta(pos)

      node_meta:set_string("arena", itemstack_meta:get_string("arena"))

      return itemstack

    end,