S3·E23 Round and Round, Pt 3
Aired October 29, 1966
Synopsis
When Underdog gets dizzy during an interview after returning from a strange planet, he is rushed to the hospital where the doctors try to find the cause. Meanwhile, the alien grows so big, he breaks out of the lab where he was being examined. Underdog hears the cries for help and leaves the hospital to face the now giant alien. But the charm around his neck causes him to get dizzy, and the giant toys with him.