PROVO, UT (WCMH) – People are wondering if a BYU professor’s alleged prank went too far when one female student volunteered to drink his “urine” for extra credit.

According to KSTU, the student received extra credit for drinking the liquid in a small vial that was said to be the professor’s urine.

The professor, Jason Hansen says it was all party of a lesson on kidney function. Three days after the incident he posted the following note: “Please rest assured that it was not really urine but rather food coloring and diluted vinegar.”

Hansen told KSTU he had performed the same gag with other classes, and that he’d usually let the students in on the prank the next session.

“She could have said no but at the same time, I feel like that was a disadvantage to me and the rest of the students who didn’t want to drink his urine,” said one student.

Hansen said the lesson showed how the color of urine shows how well your body conserves water.

BYU administration declined to comment on the incident.