Episode Recap: A Wasteland of Rehashed DreckWhat is 4/20 and why does it make humans giggle? Plus, a joyous celebration of Tax Day.Apr 9, 2019, 3:20 PM ET What is 4/20 and why does it make humans giggle? Plus, a joyous celebration of Tax Day.How to WatchCatch up on Alien News Desk on the SYFY app.