Dark matter monsters : cryptids, ball lightning, and the science of secret lifeforms

Thousands of people have witnessed bigfoot and other strange creatures for decades in North America and worldwide. In many cases, these encounters have been followed up and documented, including physical evidence by trained investigators. Is bigfoot an undiscovered primate, a relic hominid, or an alien species? And why are so many encounters also filled with unusual and extraordinary phenomena like luminosities, time slips, and telepathic interac...