We found this tiny little striped bug in South Florida, USA. It had a silken brown cocoon which it dragged behind it. It was a tiny little larva with minuscule legs, and its cocoon had two entrances. It would hide inside, then emerge out of either end to begin moving along.
I’ve never seen a bug like it, and would love to know what it is. Updated 6/4/10: it’s a plaster bagworm, and that wasn’t its cocoon, but its home — and it’s a pest. Thanks Andrew!