The Sunday scaries recently took on new meaning for avid New York Times crossword solvers.

For the first time in the famed puzzle’s 84-year history, a printing mistake rendered it impossible to solve.

The puzzle—created by Michael Lieberman and titled “Nuclear Fusion”—was published in the April 19 issue of the New York Times Magazine without a clue for 5-across.

“Sunday’s crossword puzzle in the print edition of The New York Times Magazine contains a grid that does not match the clues,” the outlet cautioned on X (formerly Twitter) on April 18, before the magazine hit shelves. “The correct version of the puzzle can be found in the news section of Sunday’s print edition of The Times. The puzzle on our app is correct.”

So, how did the wrong puzzle get included in the Sunday edition of the newspaper?

“After the issue had already been printed, we discovered that there was an error with the solvable grid,” an editor’s note published online April 18 read. “We sincerely apologize for the confusion.”