A single purpose folder little kiddies buy when they are going back to school. Not to be confused with a duotang because the monotang only serves one purpose; to hold paper.
This is the phenomenon where, after drinking a highly caffinated energy drink, the person becomes highly agitated and iritated, and generally a pain to be around.
Last night Brent had about 4 energy drinks, by the end of the night I couldn't even be in the same room with him because of his monstanger.