Batkid Defeats the Joker on ‘GMA’ (Video)

Just 10 days after he saved San Francisco, Batkid (aka 5-year-old Miles Scott) flew across the country to help the real Gotham, New York City, on Monday's Good Morning America.

Batkid captured the attention of San Francisco, people across the country, who followed his escapades via a live stream, and even stars like real-life Batmen Christian Bale and Ben Affleck, when he spent the day fighting the Riddler and the Penguin in the Bay Area.

PHOTOS: Batkid Saves San Francisco, Becomes Live-Stream Sensation

Scott, whose cancer is in remission following a treatment of chemotherapy that ended this summer, told the Make-A-Wish foundation that he wanted to be the Caped Crusader, so the Bay Area branch set up a day's worth of crime fighting.

On GMA, Batkid defeated the Joker, who'd captured American Music Awards host Pitbull and trapped him in his dressing room.

But before that, Batkid and his family hung out with GMA co-hosts Josh Elliott and Lara Spencer in the makeshift batcave created on the set of the ABC morning show.

There, Batkid got a pre-taped message from New York City mayor Michael Bloomberg, who appeared to be in a cave of his own.

"Hey, Batkid, it's great to welcome another brave crime fighter to the real Gotham, New York City," Bloomberg said.

STORY: Batkid Saves the City, Makes Everyone's Day

Miles' dad, Nick Scott, also said that he never expected his son's crime-fighting-mission to draw as much attention as it did.

"We never expected anything like this, on a level like this," Nick said.

Nick added that since his son is done with chemotherapy and his cancer is in remission, his crime-fighting is a way to celebrate the next chapter in his life.

"This has kind of been like the after-party for him," he said. "Chemo…that's all he's ever known, he was diagnosed at 18 months. But this is kind of a way to celebrate that ending."

Watch Batkid's full appearance on GMA below.

Hilary Lewis