What is hidden in 3D image?

Two doctors were in a hospital hallway one day complaining about Nurse Jenny. "She's incredibly dumb. She does everything absolutely backwards." said one doctor. "Just last week, I told her to give a patient 2 milligrams of Percocet every 10 hours. She gave him 10 milligrams every 2 hours. He nearly died on us!"
The second doctor said, "That's nothing. Earlier this week, I told her to give a patient an enema every 24 hours. She tried to give him 24 enemas in one hour! The guy nearly exploded!"
Suddenly, they hear a blood-curdling scream from down the hall, "Oh my gosh!" said the first doctor, "I just realized I told Nurse Jenny to prick Mr. Smith's boil!"