This was Jackson Bostwick's final episode as Captain Marvel.
Jackson Bostwick was fired from the show after filming of this episode and replaced by John Davey. According to an interview with Bostwick, he failed to show up for the next filming and the producers at Filmation accused him of holding out for more salary. The truth was, Bostwick had injured himself during the last filming and was late to the shoot because he was getting treatment. Bostwick ended up filing a lawsuit against Filmation and was awarded his salary for the remaining episodes of the season
Radames Pera (Rafael) also played on Little House on the Prairie for two years; yet he's more well-known for playing young Kwai Chang Caine on the popular Western show Kung Fu.
Dabbs Greer (Seldom Seen Slim) is well-known for playing Reverend Alden on Little House on the Prairie. He also married Mike and Carol Brady in The Brady Bunch pilot.