A Yolo Yellow Tee!
Now here's an odd bird. How did this shirt even happen? It isn't terrible, and it is excellent for Eggfans, but it seems like a quite-unlikely item. It's all pale yellow, with rainbow pastel for the writing that spells out "Dr. Eggman" in a ring around his face. The bottom has #Yolo (hash-tag yolo = You Only Live Once) also in rainbow pastel. The modern Eggman face has the mustache going in 2 bit of different directions as he is smirking.
Eggman has never been associated with saying 'yolo'? Is rainbow pastel his best color? Is it a meme?

This appears at Target in 2021 / summer. (It's actually a better look at the online item/this is it appearing on Gear for the 2nd time because you can actually see the design this time) It's guarenteed to be a unique item for any Tee collector and another must-get for Egg fans.