"For Amusement Only" is a Ditko-drawn story from Outer Space #18. And it's a doozy.
We start with a guy that only Ditko could have drawn, a big-wig botanist, making an observation about plant growth.
His observation that it's been growing quickly suddenly takes an absurd turn...
Putting his expertise, not to mention the narration, further into question is the fact that news of this sudden change is swiftly brought into the office by somebody else.
And the plants do exhibit fantastic growth.
Things swiftly start to look rather like this story, but worse, since they don't have atomic spaceships and whatnot.
Not to mention that the option taken by the parties in that other story aren't even working here.
They can't even kill them with fire.
World leaders are forced to coordinate large-scale evacuation efforts, but traditionally vegetation-light areas are also succumbing.
Even mountain ranges offer no refuge; only one landmass and the oceans offer places to stay. (Never mind that the oceans have plant life too.)
Things are looking very bad. Then, suddenly...
Wait, what? What?
All of these problems have been caused... by a possibly teenaged girl/woman? (On the greatest planet in the universe!!)
Things go more or less back to normal, and...
I really don't know what else to say about this story, other than the fact that the reason behind all of it is really inventive, amusing, and absolutely terrifying, by the standards of its genre and time.