It was as much of a surprise to science teacher Blaise Eitner as it was to the students when the speaker for the Black History Month assembly turned out to be actor Samuel L. Jackson. While Jackson told the school about his career, Eitner slipped out of Taper Gym and went to his marine biology classroom, where he happens to keep his 16-year-old copy of the script for “Deep Blue Sea,” a 1999 movie co-starring Jackson.

When Jackson was about to leave, Eitner stopped him and asked for his autograph on the script. Eitner worked as a scientific consultant on the script in 1997, when he was a graduate student.

The 1999 trailer for “Deep Blue Sea” features a scene in which a marine biologist character shouts, “That’s impossible! Sharks do not swim backwards, they can’t!”

This exclamation was one of the “ridiculous ways,” according to Eitner, that he found his scientific feedback on the script incorporated into the final movie.

“It was as if the sharks had gotten so smart they could violate physics,” Eitner said.

When Eitner was doing his postdoctoral research, he became known in the field of marine biology as a shark expert, he said. As a result, he got a phone call one day requesting scientific feedback for a movie about sharks. Eitner agreed, received a copy of the script in the mail and began giving feedback to the screenwriter in regular phone calls, pointing out numerous simple mistakes.

“Among other things, sharks don’t scream, sharks can’t hover,” Eitner said. “A number of things didn’t make their way into the final script because they were ridiculous.”

Although Eitner had been promised that he would be paid for his work, he never received any checks in the mail, so he stopped making revisions and calling up the screenwriter, who never called back.

Since he thought that the payment was negligible, he didn’t bother asking for it, instead receiving his payment 16 years later with the autograph.

“That’s worth more to me than I would have gotten making a little money from the job,” Eitner said.