Morichro was an ancient Jedi art that allowed its users to rapidly slow down the bodily functions of an opponent to the point of death. Master Yaddle was one of the few members of the Jedi Order permitted to practice that dangerous technique.
In the current Star Warscanon, morichro was first mentioned in Star Wars Character Encyclopedia: Updated and Expanded, a 2016 reference book authored by Pablo Hidalgo. In the Star Wars Legends continuity, the Force power, albeit unnamed, first appeared in the 1994 novel Champions of the Force, written by Kevin J. Anderson as the last novel of the Star Wars: The Jedi Academy Trilogy. Morichro was first named in the article «The Emperor’s Pawns,» which was published in the fifth issue of the Star Wars Gamer magazine on July 24, 2001.