New Super Mario Bros. introduced other types of Mushroom power-ups , such as the `` Mega Mushroom '' , which causes Mario to grow to screen-filling proportions and the Mini Mushroom that makes him shrink to a very small size . Throughout the series ' history , there have been several kinds of Mushroom power-ups , including the 1-Up Mushroom , which gives Mario an extra life ; the Poison Mushroom , which causes Mario to either shrink or die ; the Mega Mushroom , which causes Mario to grow very large ; and the Mini Mushroom , which causes Mario to shrink .