Michael J. Fox is spilling some time-travel tea in his new memoir Future Boy: Back to the Future and My Journey Through the Space-Time Continuum. Fox claims his Back to the Future co-star Crispin Glover — who played his on-screen dad, George McFly — was brilliant but chaotic on set, creating real tension with director Robert Zemeckis and writer Bob Gale. Fox wrote that Glover constantly ignored camera directions, wandering out of his marks so often that the crew literally built a “mini corral” out of sandbags and C-stands to keep him in the frame. Still, Fox insists there were no hard feelings, calling Glover “unquestionably talented” but “unpredictable,” admitting there’s “no way to prepare for Crispin.” He even compared Glover’s wild energy to Christopher Lloyd’s Doc Brown style — never the same take twice.