This is a copy of Sub Mariner #16 published by Marvel in 1969. Cover pencils by Marie Severin, inks by Frank Giacoia. Script by Roy Thomas, pencils by Marie Severin, inks by Mike Esposito (as Joe Gaudioso).
 
First 15-cent cover-price issue.
 
"The Sea That Time Forgot!", Namor is informed that Tiger Shark has been seen near the Sargasso Sea and he makes his way out there; He confronts Tiger Shark who has allied himself with a group of Immortals bent on ruling the world; However, when the Immortals leave the mists of the Sargasso Sea, they begin to age instantly and die; Tiger Shark attempts to unleash a deadly virus, but Namor and the sacrifice of Dr. Newell ensure that it causes no harm; Unfortunately, Tiger Shark escapes, but Namor vows to kill him when they next meet.