Amazing Spider-Man #75 Aug 1969
"Death Without Warning!"
Spidey, aware that Dr. Connors and his family are in danger from the Maggia, searches for them;
The once-elderly Silvermane tries to convince Marko and Cicero that he is in fact
a younger version of himself while Dr. Connors escapes and Spider-Man arrives;
In the ensuing free-for-all Connors transforms into the Lizard
…and Silvermane just keeps getting younger.
Script by John Romita (plot) and Stan Lee (script), pencils by John Romita (layouts)
and
Jim Mooney (pencils), inks by
Jim Mooney https://alchetron.com/Jim-Mooney