Mac Tonnies was an American author and blogger with an interest in cosmology, nonhuman intelligence, UFOs, consciousness studies, and futurism. Through his blog Posthuman Blues, he developed a a "small, but devoted" readership as described by The New York Times in a 2011 article. He also developed the "cryptoterrestrial hypothesis." suggesting that some UFO and alien sightings might be of potentially unknown but earthly species in origin. He died of cardiac arrhythmia in October 2009.