Imagine walking down the street and running into an Ankylosaurus. Its heavy, plated body and thick spines would surprise anybody! But despite its size and armor, this 'stiff lizard' could move pretty quickly when it needed to. Discover how Ankylosaurus continues to surprise scientists--and unsuspecting readers--to this day. Additional features to enhance comprehension include informative sidebars, a glossary of key words and phrases, sources for further research, a Did-You-Know section, and an overview of the geologic time scale.