Disambiguation: from Challengers of the Unknown
First published in: 1957
Rocky Davis first appeared in Showcase (DC, 1956 series) #6 (January-February 1957). His full name was given as "Leslie Davis" in Challengers of the Unknown (DC, 1991 series) #2 (April 1991).
Link: https://en.wikipedia.org/wiki/Challengers_of_the_Unknown