This Super Mario Bros. t-shirt features an image of the green 1-Up Mushroom. The shirt reads Get A Life.

The 1-Up Mushroom first appeared in Super Mario Bros., where it could normally be found in hidden blocks. When Mario would pick it up, the mushroom would grant Mario one extra life. The 1-Up Mushroom is one of the rarest mushrooms to find in every Mario game.
Super Mario Bros. is one of the most popular and influential video games of all time, and everyone will know that you are a fan when you wear this 1-Up Mushroom Get A Life Super Mario Bros. T-Shirt!