Wrist pin retainer and I suspect a chunk of piston, that circlip is not working its way past the piston without damage and the little end pin will be rubbing on the bore scoring it. Strip down time.
Although this doesn’t change the outcome of a strip down, if memory serves me correctly, the V6 piston Gudgeon Pin clip can drop out and get past the piston with no damage as the piston doesn’t have a full skirt. It is cut away for the pin and clip on the sides and as the top ring, middle ring and oil ring are above the gudgeon pin, it has nothing to stop it falling downwards. The full skirt IS on the con rod stroke sides. As said above though, the un-restrained pin will do some damage. I may be wrong and stand to be corrected without being offended.
As I say, it changes nothing as the clip needs replacing to stop the pin moving, so a strip down/rebuild is inevitable.
Not what you need to hear I know.