Mario's mushrooms that make him grow to his "full size are in real life called the Fly Agaric...
--- Below taken from www.mong.tv ------
for those who think they made mario a "shroomer" or druggie... consider the Fly Agaric is not a Psilocybe - aka - a "Majik Mushroom"
the Fly Agaric its self are sometimes mistaken for psycadelic shrooms by novice shroomers and when taken in large quantity, can and may cause a systematic shutdown of the faculties of the liver, your bodies natural "waste filter", which sadly doesnt even noticably kick in until 3 days after injestion...by which point its "too late" your body is poisened by its own wastes and you actually die a painful death...
any initial response to the ingestion will likely be nausea and headache...
in conclusion... if mario's initial programmers were trying to spoof shrooms into the game...they did a piss poor job
the shroom is depicted below...