Brave And The Bold (1955) #157
Starring Batman and Kamandi, the Last Boy on Earth. Extortion, Inc. is hard at work in Gotham City twisting the arms of the rich and powerful to build their own coffers of ill-gotten gains. And the word on the street is the gang has gotten a lot stronger since recruiting a new thug, an indestructible kid they call the Enforcer. Gotham P.D. reports hitting this Enforcer with shotgun fire to no effect. And sure enough, when the Batman sets up a sting to catch this new crook, the Enforcer easily bats our Bat away!
However, remarkably Batman notes that this new Enforcer is none other than Kamandi, the lone human survivor of a future world ravaged by the Great Disaster, apparently hypnotized into a life of crime. Leaving the mystery of the boy's time travel aside for the moment, our hero concentrates on bringing him around to senses before Extortion, Inc. decides to flood his system with a deadly toxin! "Time...My Dark Destiny!" is written by Bob Haney and drawn by Jim Aparo.