Josh Walker was an average Kansas teen that enlisted in the U.S. Army. He was selected without his knowledge to be a new Doomsday. Developed by Amanda Waller, All-American-Boy had the abilities of Doomsday as he got the injection of his DNA and the Kryptonite as a binding agent. He fought Superman and nearly killed him, until Batman arrived with the parents of Josh, so the latter calmed down and stopped his rampage when he saw them.
Powers, Abilities, and Skills
After an injection of Doomsday's DNA, Josh apparently gained his look and the powers as well. Furthermore, he had kryptonite flowing through his body and his bones now were made of kryptonite instead of rock. When Superman fought him, he felt de-powered with every minute because of kryptonite. Batman launched missiles that were capable of destroying mountains, but they didn't even slow down All-American-Boy. He was only defeated when his parents arrived and made him stop, because he still remembered them.