Who knows what lurks inside? I guess whoever placed it and used a wrench on it to set the destination.
Cave Entrance price in Growtopia: sells for about 5/WL (median of 11 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: OPCITY, WUEHH, ATFAN, CEBOW, MURABLOCK