UFO Robot Grendizer vs. Great Mazinger (UFOロボ グレンダイザー対グレートマジンガー, UFO Robo Gurendaizā tai Gurēto Majingā) is a 1976 animated short film that crosses over Go Nagai's super robots Grendizer and Great Mazinger.

The film was released in almost all countries where the original Grendizer and Great Mazinger series were also shown, most prominently in Italy, France and the Middle East.

After many attempts to destroy Grendizer and conquer Earth, King Vega sends General Barendos and his troops in a special mission.

Before landing, Barendos stops at moonbase and warns the two officials there that in case of his success they will be both dismissed and killed.

In the forth chapter (titled Terror of the Two Demons) of one of the Grendizer manga adaptations, Koji Kabuto and Tetsuya Tsurugi are mind controlled by a brain wave machine created by Vegan Commander Depel.