It isn't part of regular continuity. It is an alternate dimension that was first visited in Ultimate Fantastic Four #20. The original Marvel Zombies mini series which was written by the god among men Robert Kirkman is arguably the most popular comic since The Death Of Superman, every issue except for #2 had multiple print runs with issue #1 topping them all with like 4 reprints. I'm sorry, sometimes the comic book nerd in me comes bursting out. Anyways, the covers all depict zombified versions of classic Marvel covers beatifully illustrated by Arthur Suydam. Could anyone have done a better job with this series? I don't think so. Anyone, comic fan or not should get themselves a copy of the Marvel Zombies Hardcover which can be purchased at basically any comic shop. It's well worth the 25 dollar price tag and beats the hell outta payin' around a hundred bucks to get the original comics "which I have by the way, including all variants", sorry, there goes that comic geek thing again. Marvel Zombies and The Walking Dead are the reason I got back into comics after over a decade of not giving a shit about them, Robert Kirkman is responsible for both. Robert Kirkman is a genius. Hooray Robert Kirkman. ahem ROBERT KIRKMAN! Did I mention Robert Kirkman?