I think that some of the shifting pixels could have occured from vapors caused by the landing.

I don't think that wet sand or clay could shift like that without actually seeing wakes or tides (maybe something similar to the Florida Everglades), but who knows at this point.

[One reading from an instrument protruding from the front of the saucer-shaped craft to gauge how deeply it penetrated upon impact suggests that the moon's surface is the consistency of wet sand or clay.

"We think this is a material which may have a thin crust, followed by a region of relatively uniform consistency," John Zarnecki, the scientist in charge of experiments on Titan's surface, said.

Dr Zarnecki says one of his colleagues has suggested another analogy: creme brulee.

"But I don't suppose that will be appearing in any of our papers," he said.]

From: http://abc.net.au/science/news/scitech/SciTechRepublish_1282629.htm

Those readings were taken by this nifty gadget (penetrometer sensor head):

http://www.lpl.arizona.edu/~rlorenz/acce.pdf