Hadley (aka Bernie Kosar) from The Power of Six is a chimera, which is a type of sentient animal shapeshifter. They can only shift into other animal forms, but most often, Bernie Kosar takes the form of a small beagle. His real name on Lorien was Hadley, which John Smith remembers when he has visions of Lorien. Bernie Kosar was given to John by his family on his home planet and he protects John and the others.
