You always bring me joy.

 

The best thing is when I see something so beautiful. The only problem is, sometimes I don't get to see it at all." - The Joker

He also says:

He is always on my shoulder. It's hard for me to tell the truth to him.

He makes reference to the Batmobile once again:

And that's why I wear a helmet and a hat!

Batman: Arkham Origins

The Joker gives an insight during his final conversation with Harley Quinn, telling her to take a look at the scene of Robin and Harvey fighting over his severed head.

In Arkham Asylum: Extinction, the Clown Prince of Crime (rebranded as The Joker by an audience member) is the only antagonist in the game to mention the Clown Car; he's seen briefly in the player's starting area, where he is first encountered. In the game's opening, when the heroes are discussing how to defeat the Scarecrow, they mention the car and refer to what he did in Arkham Asylum, calling it "The Joker's Vehicle". He mentions that Robin, also having a Joker car, took it out because the Joker wanted to take him out for himself. The Joker's Vehicle is shown in the Clown Factory, and can be picked up as a reward from a cash merchant, as this is a reference to the car that Harvey used to kill Bruce Wayne. While the player cannot use this vehicle in any way (a variant is also available for multiplayer), it can be purchased by defeating The Scarecrow multiple times. The only time The Joker's Vehicle is mentioned out loud is when he says something to Harley, who then turns around and says something in his accent.

The Clown Prince of Crime's car in Arkham Asylum: Extinction A toy replica for the Clown Prince of Crime's vehicle.

During The Dark Knight's battle with the Joker in Wayne Manor, the clown prince attempts to intimidate the Batman by saying: "There's another way you don't look. The Joker is right up your alley..."

During the game, it's revealed that he is able to talk directly to Alfred with his thoughts and makes jokes, and his car's horn, when mentioned, is clearly heard.

During the scene in The Dark Knight's flashback on the roof of Arkham City, the car is seen again, but this time it's seen moving backwards rather than spinning. This implies that the Clown Prince (as he is in the game) will return in a future Arkham City expansion.