Space Ghost and Dino Boy (1966)

S1E5 The Moss Men

As they flee from a T-rex, Dino Boy and Ugh find themselves ensnared by the Moss Men after tumbling into a water-filled pit that leads to their underground hideout. The Moss Men intend to make Dino Boy a sacrifice. Ugh must confront the Moss Men and save his friend before time runs out.