There are plenty of reasons why eating feces is bad for you, and a judge has ordered the South Jersey teen who defecated in a classmate's soda to detail them all in an essay.

Prosecutors dropped an aggravated-assault charge against the 17-year-old Haddon Township High School student after he pleaded guilty in Camden County Superior Court yesterday to tampering with a food product. As a result, he'll be on probation, and must serve 200 hours of community service and apologize to the victim by letter.

Superior Court Judge Angelo DiCamillo also ordered the teen, a standout athlete at the high school, to submit a 1,000-word report, with footnotes, "on the problems and diseases associated with fecal matter being ingested by humans," the Camden County Prosecutor's Office said.

The prosecutor's office said the student, who was not identified because of his age, removed the lid and straw to a 17-year-old classmate's soda inside a classroom on March 29 and defecated in it. The victim took a sip, then spit out the soda, the prosecutor's office said.

Classmates in the auto-shop classroom who were watching erupted in laughter, the prosecutor's office said. The offending teen was charged the following day.

District Superintendent Mark Raivetz said the district disciplined the teen.

The Daily News was barred from the juvenile's hearing yesterday, and his mother and father, a physical-education instructor in the Haddon Township School District, declined to comment.

His attorney said the incident was a "foolish prank."

"I'm sure he has learned his lesson," Jeffrey Zucker said. "I think it was disposed of in a proper way."