What happens when you combine hydrogen peroxide, potassium iodide, and soap? You get elephant’s toothpaste…and a gigantic mess. Despite the name, elephant’s toothpaste is not used to improve the oral care of large mammals. Instead, elephant’s toothpaste is a foamy substance that is created by the rapid decomposition of hydrogen peroxide with the help of potassium iodide. The released oxygen is then captured by the soap, transforming it into bubbles and foam. Cautionary note: Although it might look like a fun childhood experiment, the chemical reaction is highly exothermic, causing the foam to reach temperatures of 200 °F. In a recent video, YouTuber Mark Rober teamed up with Science Bob to fill a swimming pool with elephant’s toothpaste and break the current world record.