Felix "PewDiePie" Kjellberg. PewDiePie/YouTube

A plane flew over lower Manhattan on Monday with a banner that read "Subscribe to PewDiePie."

The "Subscribe to PewDiePie" meme was started as a joke hashtag based on YouTube's most popular creator, Felix "PewDiePie" Kjellberg, competing with an Indian music label for subscribers.

The phrase was co-opted in two tragic instances: to deface a World War II memorial and in the Christchurch, New Zealand, terrorist attack.

Though Kjellberg himself called to end the meme, it has taken on a life of its own.

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The battle over a top YouTuber's name is taking to the sky: A plane flew over lower Manhattan on Monday morning carrying a banner that read "Subscribe to PewDiePie."

The phrase is part of an ongoing meme campaign started by Felix "PewDiePie" Kjellberg, the Swedish video creator behind the world's most popular YouTube channel. An Indian music label, T-Series, has been challenging Kjellberg's subscriber count in a continuous battle for top YouTube channel.

Images of the plane flying over Manhattan first surfaced on Twitter on Monday:

Notably, the phrase "Subscribe to PewDiePie" has been associated directly with two tragic events: the defacing of a World War II memorial, and it was used directly by the Christchurch, New Zealand, shooter.

Because of that association, Kjellberg himself denounced the phrase and called for an end to its use over the weekend.

That apparently was not enough to stop a group of PewDiePie fans from raising funds and hiring a plane to promote his channel:

The creator of the giant banner is a group of PewDiePie fans who say the banner was an attempt to thank Kjellberg for nine years of making YouTube videos. Moreover, a representative of the group told Business Insider that it was printed by mistake, and the banner was intended to say "Thank You PewDiePie!"

"We told the agency 'Thank you PewDiePie!', but the agency told him 'Subscribe to PewDiePie' possible [sic] because they assumed everyone was doing that phrase," the project's coordinator Nan Yi told Business Insider.

"We carried on, and decided to rebrand the event as a celebration and a send off for the meme," he said.

Here's a closer look at the final banner that flew over Manhattan on Tuesday:

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