Oh, wouldn't life be swell if you could just consume mushrooms to cure all your problems. Well, at least for more than a few hours! This officially licensed Nintendo adult t-shirt features a Red Mushroom over the caption 'Oh, Grow Up!'. This red heather, standard fit t-shirt is composed of 100% cotton. Be sure to check out our Size Chart to get an idea of the average size and dimensions of this Nintendo Oh Grow Up tshirt style. Check back often for some of our new Nintendo clothing and other Mario merchandise at great prices only at AnimationShops.com.