Ending - Room For One More

[cut to Star telling a story to her two twin daughters in the future]

Star: And that's how you two were concei-
Marco:  STAR!!! You promise to never talk about that again!!!



The ending to the Goosebumps - Star Butterfly story trackforce.deviantart.com/art/…
 
 
    Hijinks ensue when Star goes crazy on Marco after he ends their couple relationship. It all came to a climax above the town's water dam where Star had to save Marco from a attack by Ludo. Star apparently perish in the battle leaving Marco sad in losing a friend but a bit happy that a crazy ex was gone.

  That night Marco decides to take a shower to celebrate, however Star herself appears right there! She survive the battle by transforming into water and finding Marco's home through the water pipes. Marco is surprise and (obviously) shocked by Star who was him cornered in the shower. Seeing that she's in power, she decides to undress and [CENSORED]
 
     Nine months later Star gives birth to twins and Marco is forced to marry Star in order to avoid execution (sleeping with a Princess out of marriage is a big crime in Mewni). Everyone but Marco lives happily ever after!


                    However it turns out that this entire story (which you read from Marco's POW) was a flashback, It is Star who's telling the story to her twin daughters! Mind blown R. L. Stine twist!