This here is Giygas.
Wear this shirt AND/OR case your iPhone with this to render those who look upon it into an incoherent babbling pool of uncontrollable madness.
Giygas is the final boss in Earthbound (Mother 2), probably the greatest RPG ever to have existed.
The print on the t-shirt should be a nice bright red, FYI. RedBubble dulls the colors out when uploading for some reason. Check out the iPhone case to see the intended colors.