ID: flatworm?

[ScienceAchieved]

It's about 2mm in length, the dorsal surface is a kind of mottled sandy color. im guessing its a flatworm, but i noticed on the right side close to the "head", there seems like there's a tiny threadlike appendage moving.
this is the best pic i could get, camera phone has trouble focusing.

Edit- i think the thread i mentioned was some kind of debris stuck to it its hard to see, and my cat stole my jewlers loop haha

 

[cloak]

Maybe this link will help.

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

 

[peasofme]

if it doesn't move, possibly a sponge