Thanks to Walt Disney World News Today, guests not at the parks (yet) can get a look at some of the current Marvel items available at the Orlando park. Since Marvel characters are still being used in Universal Studios, Disney has to find ways of having "exclusive" items.
Hanes has produced these shirts that are currently being sold in the park, but Hanes does not produce other merchandise for the Disney Parks. This is a clever way of getting exclusive items without branding them as Disney Parks.
Granted, these costume shirts are fairly common at most stores. Plus, the mouse ears are uniquely Disney. There's a whole sticky legal situation with Marvel in the theme parks — since Universal has exclusive rights — and frankly, that's a post for another day. If you're heading to the parks soon, keep an eye out for these marvelous items!