What is the joke in the last panel? Is that referencing anything in particular?

When people in hamsterballs is a more space efficient way of transporting people than cars are smh

Isn’t it not even a puzzle anymore when you have enough people around to keep the goats and wolves in check on both sides of the river and in the boat?

You have died of dysentery.

I read this and kinda checked out then looked at the last panel and got a chuckle

I mean, I’m all for the giant car pulled by 40 tiny ones.

https://xkcd.com/2684/