yeah but its pretty hard and how often do you get a mushroom when your in first anyways? i guess you can get it and hold it if you were farther back but still
i know 1 way to block blue shell too.. all you need is a mushroom, im guess one will work i had the 3 and just went nuts with it.. But when you hear the "ding ding ding" and the blue shell arches up to strike you, wait till its coming down on you and blast the mushroom, its already on its path to strike you so it wont readjust its route it will slam into the ground! hope that helps aswell