Some Forbidden Planet trivia from Wikipedia:

The animated sequences of Forbidden Planet, especially the attack of the “Id Monster”, were created by the veteran animator Joshua Meador, who was lent out to MGM by Walt Disney Pictures. According to a “Behind the Scenes” featurette on the film’s DVD, a close look at the creature shows it to have a small goatee beard, suggesting its connection to Dr. Morbius, the only character with this physical feature…

I’ve seen the flick many times, but never noticed a goatee before.