Watch Reactor Online Free at Couchtuner. Reactor is a new, weekly series sitting at the intersection of pop culture and science fiction that captures and celebrates all the things sci-fi fans are talking about each week. Reactor is hosted by David Huntsberger, comedian and genre superfan. Through David’s unique and irreverant point-of-view, Reactor will cover everything going on in the sci-fi genre (from movies to TV to video games to comic books) via celebrity guests, sketches, mash-ups and more. (Source: Syfy)