A Mega Mushroom is a mushroom that Mario and Luigi use in NSMB DS. It allows them to turn big for at least 15 seconds, stomping through enemies, bashing through blocks, and smashing pipes. There are some consicquences about the Mega Mushroom:
  • Mario or Luigi wont be able to fit in pipes
  • Sometimes they might be to big because the celing of the level is to tiny
  • they cannot get any items

cant climb vines

There are also good things about it:

  • When you are playing a lava level, when you fall, they shrink to normal size then die
  • Sometimes easier to get starcoins

Overall, the Mega Mushroom is a pretty useful item.