If Martha Graham had choreographed a dream sequence in Weird Science with the cast of Fraggle Rock, it would still be only half as good as the Bland presentation. In Cherry Lane Theater on elusive Commerce Street, this was a civilized affair, with the Deitch Projects clan and their faithful gathered to observe a mysterious potted plant center stage. Officially titled The Miraculous Conception of Beast Jr., the presentation was the joint effort of designer Theodoric Bland Willoughby (yup, that’s his name) and Megan Coleman, both committed to pushing the boundaries of fashion with their uncompromising projects. Mime dancing, underground lairs, they’ve…