The Joe Cool Shirt is a clothing item that is currently available. It is on clearance.
Official Description Edit
"Add a Joe Cool shirt to any furry friend for a classic Peanuts look. The red tee says "Joe Cool" in black lettering and is paired with a connected black jacket." 
The Joe Cool Shirt is a red shirt that says in black writing, "Joe Cool". The Joe Cool Shirt is attached to a plain, black jacket.