This could be called a "derivative" work of art possibly, but it is an original painting with its own features. This is not plagiarism and Yatsan is well within their rights to do this as parodies are also protected. It seems like a few people here are intent on casting aspersions upon Yatsan.
I find it interesting that user @2weent6 woke up from a year long inactivity, and that was his first post. Call me paranoid, but i wouldn't be surprised if that is an alt of some contestant.