Poor Ray Milland. Once the highest-paid, most acclaimed actor in Hollywood. Then, stuff like this. Ending with Frogs (q.v.). But I digress...

Dr. James Xavier (See the "X" in his name? See it??) develops special eye-drops that lets creatures see through solid objects. So what if it killed the monkey? He's determined to try it on himself. When he accidentally kills his colleague (a moronic death which must be seen to be appreciated), he goes on the run from the law and becomes a stage act. Eventually, his addiction to the substance makes him see more and more things he doesn't want to, until he meets a Bad (Movie) end.