Rick And Morty is one of the best cartoon shows out right now. The adult cartoon genre is ever expanding, but Rick and Morty reigns supreme as the new king of the throne. There was a time where The Simpsons, Family Guy, and South Park sat on top, but Adult Swim has their foot on the gas with Rick and Morty, which has powered to the front of the line. As reported by UPROXX (via Reddit), it appears that series creators Dan Harmon and Justin Roiland placed a Batman reference in their show. 

In the post-credit scene of the "Pickle Rick" episode, Rick and Morty are captured by a villain named Concerto. They are tied down inside a piano, and are threatened with certain death until they are saved by Jaguar. 

The scene is a direct reference to a moment in The New Batman Adventures. In the episode entitled "Legends of the Dark Knight," Batman and Robin are tied down inside a piano while the Joker attempts to kill them using a similar method. 

The scene from  "Legends of the Dark Knight" is also a nod to an older Batman scene. In the original Batman televsion series with Adam West, he and Robin are tied down while Liberace (who guest starred as a villain) plays the piano to their doom.