Fecal matter that is not completely diarrhea, yet not solid either. Also known as the triple s' (semi-solid shats), the nixons commonly have the look and consistancy of seaweed. Usually appear the next morning after a long night of drinking. Many times they "attack" suddenly and without much time to react.
"Dan had to run to the bathroom as fast as he could cause he was attacked by a case of the nixons."