Voiced by comic actor Wally Cox, Underdog always spoke in rhyme. Although the lead character was a clear parody of Superman, his series found a devoted following for a while due to its charm, its subtle satiric jabs at the politics of the day, and its love of unabashed puns. (For example, one foe was a race of flying saucer-shaped robots with the ability to cast magical spells: naturally, they were called 'Flying Sorcerors'.)
In order to encourage children to take their vitamins, many episodes would have a moment when an overwhelmed Underdog would chant the following:
"The secret compartment of my ring I fill
with an Underdog Super-Energy Pill!'
Then he'd pop open his ring's secret compartment, swallow the pill, and find himself with a brief power-up. During the series original runs, many small children would recite that same chant just before taking their own nightly vitamin pill.
Unfortunately, over the years, this pro-vitamin tablet sequence was reinterpreted as involving illicit drugs, and so many reruns of the series now edit out that moment.