As the animation shows, we seem to have an empty sample tube, which presumably means that the sample crumbled during coring.
I'm not surprised that we had a difficult time here - the rock in this area shifted and fractured before we ever drilled or abraded (even as Percy was driving over it), and we can see that we're dealing with a pretty messy scene:
Regular readers here will find this familiar - we've had sampling failures from our very first attempt on the crater floor a few months after landing, to our current operations on the crater rim, where we've had four such incidents before this latest, albeit in different terrains.
This is the first coring attempt in about 120 sols, our first on this particular section of the rim, where we've been for the last 2 months. We abraded here a few weeks ago (abrasion patch #48) and found a very interesting grab-bag of material (click through for more detail on the figure):
How about it, science team? This stuff seems like it's worth a second try, and this rover lives up to its name...