xkcd #3271: The Princess and the Pea
Title text:
Once we've fully explored this space, we can start varying the number of princesses.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3271/
Forgot the number of princesses per mattress. Maybe some blood sucking bed bugs could be added to the plot?