Researchers at the University of Delaware's ORB LAB posted this photo of a shark within a shark on Facebook in late July. The lab memebers were using a small fish called a menhaden as bait to recapture sharks they had previously tagged.

According to the Facebook post, a 3-foot-long shark known as a dogfish swam up and snatched the bait moments before a large female sand tiger shark swallowed the dogfish.

http://www.huffingtonpost.com/2013/08/15/shark-within-a-shark-phot_n_3761489.html