Rick and Morty season 4 Easter egg includes Simpsons and South Park references

This week’s Rick and Morty season 4 adventure "The Vat of Acid Episode" sure wasn’t shy about advertising its headline act – the Vat of Acid played a central role in the episode’s universe-shifting shenanigans. Morty’s ‘save point’ gadget also featured a pair of well-hidden Easter eggs, referencing both The Simpsons and South Park.

Both Rick and Morty Easter eggs appear after Morty starts messing around with Rick’s invention, which allows his grandson to save his place in time and go back to it with a simple button press.

One of Morty’s first acts is to help an elderly man. In the background, you might see a distinctive green and orange stained-glass window. Yep, that’s almost certainly a nod to Springfield and, specifically, Moe’s Tavern (as spotted on Reddit).

The Simpson's homage in S04E08 - The Vat of Acid from r/rickandmorty

Later, in the extended sequence featuring Morty falling in love with an unnamed woman and ending up in a plane crash, one of the survivors has a blue and red beanie on, the exact same design worn by South Park’s Stan Marsh.

Stan Marsh's Hat Reference from r/rickandmorty

As we find out, Morty’s button presses actually caused a multiverse split, sending several dimensions’ worth of Mortys to die. That also means Rick and Morty, briefly, may have actually spent time in the universes of The Simpsons and South Park.

Here's how to stream Rick and Morty online

But the animated crossovers didn’t end there. Rick even finds time to take a meta jab at the season 4 episode’s premise, saying it’s something that has already been done by Futurama. Which is true: the series finale had a Time Button, which rewound time by ten seconds every time it was pressed.

Original or not, it certainly ranks up there as one of the series’ most captivating episodes – with more than enough Easter eggs to warrant repeat viewings.

For more from Springfield, South Park, and wherever the hell Rick and Morty live, check out these best-of lists...