Pretty incredible...
http://www.huffingtonpost.com/2008/12/03/dog-saves-other-injured-d_n_148238.html
That is pretty amazing. My beardie would probably do something like that. He used to protect our chickens all the time. If a stray came into the yard, the chickens would all run into Grover's dog house, the rooster would perch on top and crow like nobody's business, and Grover the Dog and Samson the Cat would stand guard at the door to eat alive any critter that proved threatening. Grover would also protect Samson if another cat attacked him. One time, Grover and Ornery dog were both inside and a neighbor cat attacked Samson just outside the window. Ornery was sleeping right under that window inside the house, and when Grover heard the cat holler, he jumped up and thrashed Ornery because he thought that he was bothering the cat. He also is very protective of our middle daughter. He doesn't even like me to tell her "no"... when I do, he stands between me and her and growls at me.