Brainchild, a somewhat creepy-looking mutate, tells Professor Xavier that he watches "the equipment while the master is away." This is a reference to Manos: The Hands of Fate (1966), a film that features a creepy-looking satyr named Torgo who "takes care of the place while the master is away".
DEBUT: Ka-Zar & Zabu in the Savage Land.
DEBUT: Lupo & Brainchild in the Savage Land.
When Morph is shown doing his Dr. Jekyll and Mr. Hyde performance his appearance is based on Calvin Zabo aka "Mister Hyde", Marvel villain of Daredevil and Thor. This marks the character's first appearance on television.
Magneto identifies the leader of his "mutates" as Sauron. In The Lord of the Rings, the wizard Gandalf leads the fight against a villain named Sauron. Both Magneto and Gandalf were played by Ian McKellen.