Slugger the Junior Dynamo was a sidekick, partnering with the All-American. His "civilian" name was never revealed to the public at the time, but he was rumored to have been part of the Commando K project.
In 1943, alongside the All-American, he prevented a robbery attempt by the Time-Keeper.
- Creator Kurt Busiek mentioned Slugger's civilian name circa 2008 in the now-defunct Brusier's Comic Forum.
- There is conflicting information about the All-American. One report has him being killed by a sniper's bullet in the Korean War. Elliot Mills states that the All-American, along with the Lamplighter, had just retired in 1959. One possibility is that Slugger assumed the role for several years after Appleton was killed.