from Amazing Spider-Man Annual #2 (1965)
First appearing (as just Mac Gargan) in Amazing Spider-Man #19 (December 1964), Gargan becomes The Scorpion in Amazing Spider-Man #20 as part of a plan by Jolly J. Jonah Jameson to capture Spider-Man! (Ooooops!)
and from
The Official Handbook of the Marvel Universe Vol. 1 No. 9
(September 1983)