Amphibians: Being called "cold-blooded" is no insult to these creatures! The Science Guy explains how amphibians can live both on land and in water, and the mysterious process of metamorphosis. The show includes another original music video, "Touch me I'm sick" by Mud Puppy. Invertebrates: You may not believe it, but these "spineless wonders" far outnumber those of us with backbones. Bill shares invertebrates' unique characteristics and explains why we are dependent on them. The show includes the music video "Crawlaway," a parody of Janet Jackson's hit "Runaway," perfomrned by Spineless Joe Jackson.