There is at least one fifth-grader who will not soon forget Ben Carson’s visit Thursday to Cedar Rapids, Iowa: The one whom Carson helped single out as his class’s “worst student” before a crowd of hundreds.

It happened when the Republican presidential candidate was trying to make a self-deprecating joke about his own academic ineptitude in grade school.

“As a fifth-grade student, I was a horrible student,” Carson said, according to video captured by CBS News. “Anybody here in fifth grade? Who’s the worst student?”

More than a half dozen students turned and pointed at one particular classmate, according to the Des Moines Register, and the room erupted in laughter.

Carson tried to recover: “If you had asked that question in my classroom, there would have been no doubt about who it was.”

But the candidate took heat on Twitter for the unforced error.

Following the rally, Carson met with the student and told him that he hopes the child will become a neurosurgeon, the Register reported.