From the moment I saw this picture (more than two years ago) I knew there was only one storyline to go with it: a man had put on a bodysuit, he’d been a woman for awhile, and now he couldn’t locate the doohickey in the back that would let him remove the suit—and not incidentally restore its original owner to life. So yes, this is a Costume Gun story, even though it isn’t mentioned by name, and technically it could be any old artifact (magical or alien tech) that did the deed. The details don’t matter. What does matter is what happens when the device stops working—as it always does—and traps the wearer in his new female body. It isn’t all wine and roses, you realize. There’s guilt to deal with, perhaps even soul-crushing loss. But the human mind adapts to new circumstances, as it always has. And life goes on.
The last caption I wrote where a husband turns into his wife was “Naked Ambition“, although that didn’t utilize a bodysuit. Most of these man-becomes-wife tales involve the husband and wife swapping bodies (or at least roles, via cross-dressing). In fact, the only caption I could find where the man actually replaces his wife is last year’s “The Bodyswap Game“, although there the end game is quite different.