The Cretaceous world seems to have been a perilous place to scratch out an existence, a land of eat-or-be-eaten. And we have evidence of one dinosaur that met such an ignominious end as a feast for an unlikely predator. The skeleton of the dinosaur, Psittacosaurus lujiatunensis, is curled, its ribs in the sharp-toothed mouth of a predator, its beaked jaw gripped in a clawed forefoot, and with a hind foot braced against its thigh. The fact of this predation itself is not a surprise, but the predator's identity is a surprise: an opossum-like mammal, much smaller than Psittacosaurus, named Repenomamus...