The Comedy of Errors Puns

Hello,

I am requesting help with remembering a joke. Posts of this type did not seem to be against the subreddit's rules, but if I am in error, please let me know and delete my post.

Anyway, here is what I remember of the joke:

It is movie themed and it says something like this: "There should be a post-apocalyptic zombie movie with a romantic comedy element. Then we would have the world's first rom-com-zom-dom-bomb." The only thing is that I forget what the "dom" was supposed to mean and whether or not there is more to this joke, either in the set-up or the punchline. I googled it to no avail. Any help is appreciated.

Thank you