Great Scott! Batman's nemesis, the Joker, visited the Big Apple this morning and took a celebrity hostage!

But New Yorkers had no need for fear, because Miles Scott, AKA 'Batkid,' hopped on an airplane for the second time in his life and made a special trip to the Good Morning America set in NYC to save the day.

The 5-year-old cancer survivor only wanted to be Batman for a day, but even after his SF adventure ended earlier this month, Miles continues to occasionally don the superhero mask.

“He’s in remission so this has kind of been like the after-party for him, a way to kick it off,” his father Nick Scott told ABC. “Chemo is all he’s ever known. That’s the life that he’s known but this is kind of a way to celebrate the ending.”

Mayor Michael Bloomberg recorded a message welcoming him to the "real" Gotham City, shortly before the miniature superhero was called away to fend off the Joker, who had taken rap star Pitbull hostage after his GMA performance. Batkid, of course, came to his rescue just in time.

Miles' parents announced last week that they've created a Batkid Fund to benefit the organizations that helped Miles and his family through his battle with cancer.

H/T: The Daily Mail

Also on HuffPost:

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  • #SFBatkid

    This undated image released by Make-A-Wish Greater Bay Area, shows five-year-old Miles Scott dressed as batman. With the help of the Make-A-Wish Foundation and the city of San Francisco, 5-year-old Miles Scott, aka Batkid, will rescue a woman from cable car tracks and capture the evil Riddler as he robs a downtown bank. Miles, who lives in Tulelake in far Northern California, was diagnosed with leukemia when he was 18 months old, ended treatments in June and is in remission. (AP Photo/Make-A-Wish Greater Bay Area)

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    Miles Scott, dressed as Batkid, second from left, exits the Batmobile with Batman to save a damsel in distress in San Francisco, Friday, Nov. 15, 2013. (AP Photo/Jeff Chiu)

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    He's on the move! (AP Photo/Jeff Chiu)

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    Our hero! (AP Photo/Jeff Chiu)

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    Have no fear, Batkid is here! (AP Photo/Jeff Chiu)

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    The San Francisco Chronicle is the Gotham City Chronicle today!

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    Before the adventures even kicked off, the whole city prepped for Batkid's big day.

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    Even the Harlem Globetrotters lent their support.

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    So did the 49ers!

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    The Batmobile arrives! It's almost time.

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    Our hero arrives!

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    Batkid's little brother is his sidekick, Robin!

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    Batkid and Robin!

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    Feast your eyes on the bat cave!

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    A damsel in distress waits for Batkid to arrive!

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    He's on his way!

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    He did it!

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    Way to go, Batkid!

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    Even Batkid needs a lunch break.

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    Time to recharge before fighting more crime.

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    Our hero!

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    The whole city is here to see our favorite hero.

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    Oh no! the San Francisco Giants' mascot has been kidnapped!

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    Batkid has SO many fans.

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    Batkid is on his way to save the day again!

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    HE DID IT!

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    Everyone at AT&T Park loves to cheer on Batkid!

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    Our favorite hero is off to City Hall!

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    City Hall is ready for him!

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    President Obama has a message for Batkid!

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    Batkid receives the key to the city!

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    Batkid at City Hall!