haha you'll find out i bet!
Mine dident do it for quite awhile!! then.. when my bta started to touch the sand with its tenicles she started digging.
Basicly they stick theyre tail on the sand and swing it back and forth causing sand storms. I had a bit of crushed coral that would get in her way. so she picks it up with her mouth and spits it at me.
She dug all the way thru a deep sand bed until she hit the glass.
I moved not long ago and replaced the sand with finer sand, and the nem doesent touch the sand at all.
Ive only seen her do it 1-2 times in a month.
But when a 'stranger' came over she resumed spitting gravel at him. but not at me right now.....
another thing bugging me is every so often ill see her swim outta no where, take a big bite of star polyps and spit them at me. bugger. I saw a tip of my torch coral floating around the other day too.
Im leaning towards she was just trying to rearrange the tank agian and these two pieces of coral were stuck and she couldent move em... Since my kenya tree was upside down that day too *haha* they seem to really like theyre pad a certain way. and they'll move somthing if need be!