These are the (original) or like original files for the famed "Nazrin Rat T-Shirt". This was originally sold by Ahikabara (https://twitter.com/akibanext1), but this original seller has since dropped off the face of the earth, with no more sales of this shirt present.

The main place it was originally sold was here, and you could receive it from Japan in the year of 2019, but afterwards it was not possible to acquire it from any source (as of 2020) https://www.amazon.co.jp/AKIBANEXT-%E6%9D%B1%E6%96%B9project-%E3%83%8A%E3%82%BA%E3%83%BC%E3%83%AA%E3%83%B3-T%E3%82%B7%E3%83%A3%E3%83%84%E3%80%8C%E3%81%AA%E3%81%84%E3%81%A7%E3%81%99%E3%80%8D-XL/dp/B07C5Q4CTQ/ref=sr_1_5?s=apparel&ie=UTF8&qid=1527646116&sr=1-5.

I really wanted this shirt, so I blew $13 dollars on Fiverr to get someone to rip the logo and redraw the vector file from remaining promotional images of the shirt. You can check out the redrawing Fiverr artist here: https://www.fiverr.com/dawood25200

I don't know how I'm going to make this shirt for myself, but I can now walk into any store I wish and drop that fat .ai file for them to make many copies of. So can you, in fact! I don't hold any creative attachment to this shirt, I just paid someone
to steal it for me! If you wanna make your own personal copy, go ahead. If you wanna make merch and sell it, go ahead! I don't want to be attached to it, and any legal implications fall on you, but here's the source, what you do is up to you.

If this shirt were still sold, I would have paid for it in a heartbeat. Unfortunately, four hours of internet (and soul) searching has made me confident that no one is selling it (online). I hope you enjoy this rat shirt.

-san7890
the@san7890.com