Researchers used a highly-advanced CT scanner to peer inside a fragile fossil without disrupting it--and found more fossils inside.

An ancient sea urchin doubled as a vacation destination for several small, shelled invertebrates. 
Using a state-of-the art CT scanner, researchers were able to peer inside a 10 million-year-old fossilized specimen of a Clypeaster, or sea biscuit, similar to a sand dollar.
The highly advanced imaging technique showed that multiple fossilized bivalves had bored into the sea biscuit and used it as island home—a bit of a refuge.
The technology used to spot the seafloor squatters inside the urchin is