This is a copy of Sub Mariner #17 published by Marvel in 1969. Cover pencils by Marie Severin, inks by Mike Esposito. Script by Roy Thomas, pencils by Marie Severin and Jack Katz (as Jay Hawk), inks by Mike Esposito (as Joe Gaudioso).
 
"From the Stars, the Stalker," The traitorous priest Kormok decries that Namor must perform the Ritual of Renewal and dip Neptune's Trident in the flames that spawned it; Of course, it's a trap. Kormok has made a deal with an alien race that seeks to steal Earth's water and needs Namor for an as yet unknown reason; The Stalker attacks Namor, and Namor proves to be too much for the Stalker; Unfortunately, the Stalker activates a funnel beam that sucks Namor out into space.