In an unusually hands-on history lesson, the Pundits, Yale’s favorite prank society, surprised history professor John Gaddis’s “Art of Biography” seminar Tuesday afternoon with a reenactment of the film “Titanic.”

Dressed in cocktail attire, about 40 students rushed into the room. A string quartet set up in the corner as pairs danced, and waiters poured champagne into Solo cups for members of the seminar.

But an imaginary iceberg ended the revelry, sending half the performers toward two cardboard cutout lifeboats and out of the Hall of Graduate Studies classroom.

Facing imminent death, and accompanied by the string quartet, the remaining performers followed the lead of a man in a white dress and red curly wig in a tone-deaf rendition of Celine Dion’s classic, “My Heart Will Go On.”

The mannish Kate Winslet impersonator (who was not wearing underwear, to some seminar-takers’ chagrin) then sat in an empty chair next to Gaddis, and implored him to, “Never let go, Jack.”

But that’s not all. A girl, also wearing a red wig, handed Gaddis a Valentine’s Day card, with his face superimposed on a picture of Leonardo DiCaprio. “I was just waiting for the streaker,” Gaddis concluded.

Facing a stunned seminar, the history professor explained that the performance was just one in a series of pranks aimed at him. The Pundits have been taunting him ever since he told students last semester he was disappointed that the group had skipped its traditional appearance in his Cold War lecture.

The first act of vengeance came when the Pundits sent a campus-wide e-mail, purportedly from Yale Police Chief James Perrotti, warning students of diseased monkeys running loose on campus. The e-mail asked students to call Yale Police with information, but listed instead Gaddis’s number.

An ITS representative left a message on Gaddis’ phone, the professor said, to warn him that he might receive some strange messages, and told him that “counseling is available” if he needed it.

As an epilogue, a student on crutches, also dressed in white and sporting a red wig, slowly entered the room 10 minutes later. As seminar students silently looked on, the man hobbled toward the window, and dropped a locket out of the classroom window into the HGS courtyard.