A Staten Island courtroom erupted in cheers Tuesday when a judge sentenced a killer babysitter to 23 years in prison, calling it “the most disturbing case” he’d ever handled, according to reports and court documents.

“Why would anyone want to do this to an innocent 17-month-old child?” Supreme Court Justice Wayne Ozzie said during the sentencing hearing for Gloria Fields, the Staten Island Advance reported.

Fields, 32, tortured, beat and sexually assaulted Anthony Delgado while he was in her care from Feb. 19 to Feb. 21, 2016, ultimately killing the baby boy, according to a Staten Island DA’s press release.

“Gloria Fields systematically tortured [the] toddler she was babysitting, slowing killing him,” the office said. “The child’s injuries were sustained over a course of the three days and … [covered] all of the child’s body with the exception of his feet.”

Fields killed Delgado by violently shaking him, throwing him into hard surfaces and slamming his head into the ground while he was strapped into his stroller, the document said.

The crowd cheered when Ozzie told Fields that there was “no guarantee” she would get out of prison.