This is just a larva of a moth from the Family Tineidae, most probably Phereoeca uterella (known as plaster bagworm or household casebearer), or Tinea pellionella (known as case-bearing clothes moth).
As you can see, the larva of this moth...
... constructs a protective case from silk and camouflages it with other materials such as soil, sand and insect droppings. (from Wikipedia)
Here is a better picture of Phereoeca uterella, from the entomology deptartment of the University of Florida:
Here is the imago (adult), for comparison: