The Underground Undead of Utah

The first two chapters are literally just a kid cleaning his room and walking across the street. -Friend. Anyways,

the main character and his friends search for fossils in a wooded area. They

walk into a tunnel but it turns out to be a dead end. Then zombies come up from the ground and attack them. At the end of the book, the zombies go back underground. The kids nearly escape with their lives.