This episode was created to save money, because the series was going over its budget.
Although transmitted afterwards, this episode features linking scenes which are set about a week before the events in Happy Birthday, Buck (1980).
This is a "catch up" episode. The heavy use of flashbacks and minimal use of new footage meant it could be quickly produced allowing for the remaining episodes to get back on schedule.
When remembering his encounter with the Legion of Death through the memory probe, Buck says " The thing about Kellogg is that he wouldn't waste time with riddles.". Actually, he might, since Kellogg was played by Frank Gorshin, who played the Riddler on the TV show Batman.
The riddle conformed to the meter and rhyme pattern of a limerick. The limerick was invented in the 1700s, and became popular because of Edward Lear's humorous books in the mid-1800s.