The film starts out with Moochie and his brother Wilby, creating a missile interceptor in the basement. The Missile breaks a hole in the ceiling and the two are forced to patch it up. After the incident, his dad made him and Wilby give up all their pets. When he learned his brother turned into a dog, he was delighted, because he always wanted a dog, despite his father's hatred for them. He helped distract his father from learning the truth about Wilby. Wilby told Moochie about his condition, but Moochie preferred his brother as a dog.When his father found Wilby as a dog, his dad grabbed the shotgun and tried to shoot him. Moochie tried to tell his dad that the dog was Wilby but he wouldn't listen.He later tried to find Wilby, but was disappointed to see that Wilby was a human. When Wilby learned Moochie wanted to put a leash and collar on him, he scolded him saying he was through with being a dog. He attended the country club dance, where he helped notify Wilby when he was turning into a dog. He tried to help Wilby escape but was found by Francesca and Buzz.
This is the second time Kevin Corcoran played the little brother of Tommy Kirk. He previously played Tommy's little brother in Old Yeller, and would later play his little brother in Swiss Family Robinson, Bon Voyage! and the Old Yeller sequel Savage Sam.
This is the first time Kevin Corcoran would play the son of Fred MacMurray. He would later play his son in Bon Voyage!.
Wilson Daniels • Frida Daniels • Wilby Daniels • Moochie Daniels • Allison D'Allessio • Buzz Miller • Professor Plumcutt • Dr. Mikhail Valasky • Franceska Andrassy • Officer Hanson • Officer Kelly • Stefano • Dr. J.W. Galvin • Chiffon • Laura Wells • Myra • Carl • Betty Daniels • Brian Daniels • Tim the Ice Cream Man • John Slade • Katrinka Muggelberg • Raymond • Eddie Roshak • Admiral Brenner • Freddie • Dip • Howie Clemmings • Professor Whatley • Elwood • Dave Douglas • Rebecca Douglas • Carly Douglas • Josh Douglas • Dr. Kozak • Dr. Lance Strictland • Dr. Gwen Lichtman • Judge Claire Whittaker • Larry • Trey