Did my clown create this burrow for its carpet?

[Ballyhoo]

I know for a fact that I did not nestle the carpet nem around a layer of aragonite. This is clearly constructed. How did it happen? The aragonite is surrounding and nestling and supporting up the Carpet nem.

 

[James M]

The carpet moved its foot to the bottom

 

[D-Nak]

The foot of the haddoni is actually decently strong and able to dig into sand and gravel.