Boris Karloff is deliciously evil in this devious little adventure serial. Karloff shines in this sadistic role, and Myrna Loy is interesting as his deadpan bad seed. The various torture scenes are enough for me to give this flick a passing grade. There's homoerotic subtext abound when Karloff straps nearly-nude hunk Charles Starrett to a table, surrounded by several bronzed, diaper-clad beefcakes. Joel Schumacher would be in heaven. After injecting Starrett with a mind control serum conconcted from spiders and reptiles, Karloff scrapes his long fingernails seductively across Starrett's abdomen. Yes, "The Mask of Fu Manchu" is a kinky pre-Code movie. You also get the classic alligator pit, the moving walls of spikes, death rays, and Ghengis Khan's magical sword and helmet. This is good cheesy matinee fun, and I enjoyed it way more than I probably should.