A year ago, I posted this on Facebook:
There are Cthulhu-related versions of various boardgames; see, for example, Pandemic: Reign of Cthulhu.
If there’s ever a Cthulhu version of that game about making another planet more livable, I hope they call it Terrifying Mars.
And I added a comment suggesting that Terrafying would also be a good alternative, and for that matter could be a synonym for Terraforming.
Recently, I’ve been thinking again about what a horror version of Terraforming Mars would be called, and I ended up with the name Terrorforming Mars.
But regardless of which variation of the first word you prefer, it occurred to me that the second word could also be a pun, if you think of it as a verb instead of a noun: terrifying [people] mars [them].
And that led me to realize that that pun works even in the real name of the game: terraforming [a planet] mars [it].