I got a pair of Talbot damsels a few weeks ago. One of them immediately decided it wanted to live under my trachy.

The damsel would flutter in the sand and pick up pebbles to drag away, excavating a good size cave. As the lights dim out in the evening, the trachy retracts its flesh for the night, and sinks into the hole the damsel made!

The next morning, I put the sand back in order, the trachy opens happily, and damsel begins work again. I thought he'd get tired of it, but after two weeks, I got tired of it.

I got a piece of scrap acrylic and buried it just under the surface of the sand, and put the trachy in place over it. Voila! Happy trachy, happy damsel.