Scanned straight outta Harvey Spirit #1, here's the opening splash for the story which was later titled "Visitor". The story dealt with the Spirit investigating a bank robbery and getting mixed up with "agents from Mars", in the person of one Miss Cosmek (drawn to resemble Katherine Hepburn) and her leader, whom you don't see until the dryly humorous ending. But in between you get a great mix of detective story, comedy and dramatics...Miss Cosmek doesn't want to go back to Mars, y'see, and the scene in which the Spirit discovers missing gangster "Combo" Nathan in her lair is surprisingly tense. As if you couldn't tell, "Visitor" is one of my absolute favorite Eisner Spirit stories. I forget which Warren/Kitchen Sink magazines it appeared in (don't have them anymore, dammit), but it is also in The Spirit Casebook, which might be a little easier to locate.
I took this from the Harvey comic because it doesn't have the hand-lettered title ("Visitor") which was stuck on the title-less splashes by the Warren people in the 70's. I'm sure it was done for easier identification and so they could list each reprinted story on the contents page that was in every issue, but they just don't look good pasted on those often-gorgeous splash pages. Even though it looks like Eisner lettered those himself, that's long been a pet peeve of mine. The old-school comic book coloring on this particular page leaves a little to be desired (the Spirit's mask- greenish?), but it's how I first saw it.