The artist here, Maurizio Cattelan, was at a college party while studying art. They were setting around doing bong hits, and talking about art. Then, out of the blue, Maurizio grabbed a banana and a piece of duct tape and taped a banana to the wall, and said, "that is art." Everyone cracked up and laughed outrageously for quite a while... as the story goes.
Maurizio Cattelan studied sculpture, but when asked to participate in an exhibit, he fell back on his college day antics and taped a banana to the wall and titled it "The Comedian." This sparked all sorts of jovial comments and jokes about bananas. Critics even used the opportunity to wax poetic about... Is that a banana in your pocket... Knock, knock, aren't you glad I didn't say banana... the history of banana peels used in comedy... literally, there are many thousands of jokes centered around the banana.
It was a college dorm joke, which played out in a real gallery, and along comes another comedian... new crypto-currency billionaire, Justin Sun, who adds to the joke, by buying it for an offered 6 million. The pap[ers were filled with more jokes. But, Justin knew exactly what he was doing, and will live forever in art history for playing his part in the joke.
Now, you may ask, what did he buy? He bought the rights to taping a banana to the wall and calling it art, in the form of a document, filed with the copyright and trademark, blah blah blah... and a set of written directions about how to care for the art... to further the humor.
Then someone ate the banana, people protested the banana, and people roasted the banana all over social media.
This all was never meant to be a serious work of art. Nothing about any of this was serious. Some say it was a criticism of the art world. Some say a social criticism. But, it was people who don't "get" humor, or have a mean spirited humor that seemed to get angry or outraged at the whole event.
YOU ARE SUPOSED TO LAUGH AT THIS, and then you will be laughing along with the artist... which in a way is a pretty good work of art.
If you take this too seriously, you just don't have a sense of humor.