I am always amused by the construction/de-construction ability of tarantulas. My Avicularia avicularia (pinktoe) hauled a clump of moss as big as she is up 12" from the floor of its enclosure, plugged its entrance and then began to line its web with moss. The enclosure bottom is a thin layer of shredded coconut husk and a generous layer of sphagnum moss on top, now there is a big bare patch of coconut.