Marvel fans across the nation are flocking to theaters this weekend to see “Avengers: Endgame,” but one teacher who won’t be able to see the movie until next week had a strong warning for his students: No spoilers.

In a viral tweet which had nearly 100,000 retweets and 400,000 likes as of Saturday afternoon, Twitter user @kamiilious shared a photo of a sign posted on her teacher’s classroom door.

The letter — in which the teacher, who has not been identified at this time, says he will not be able to see the film until Wednesday “at the soonest" — issues a firm warning to students.

'AVENGERS' FANS CRY FOUL OVER WASHINGTON POST 'SPOILER' HEADLINE: 'SHAME ON YOU'

“DO NOT discuss ANYTHING about it anywhere near my classroom UNTIL THIS SIGN COMES DOWN. You know how much I love Marvel Comics," it reads.

The notice continues: “So help me Jeebus, if any one of you spoils a single frame of this movie for me, I promise I will make you wish that Thanos snapped your narrow a**.”

Though the note may seem intimidating at first glance, the student who shared the viral photo insisted it was only a joke.

“WE TOOK NO OFFENSE TO WHAT THE TEACHER SAID. SO PLEASE STOP SAYING ITS BULLYING OR WHATSOEVER. [IT’S] ALL HUMOR GUYS!” @kamiilious later tweeted.

“Same. I would send kids to the office so quick,” commented one person in response.

“I'd be petty and have them sent to another class for spoiling information!” shared another.

Separately, actor Chris Hemsworth revealed to Entertainment Tonight on Monday at the film’s premiere that he has mixed feelings now that his years-long stint portraying “Thor” in Marvel’s beloved “Avengers” film series has come to an end.

CHRIS HEMSWORTH ON ENDING OF MARVEL’S ‘AVENGERS’ SERIES: ‘IT’S BITTERSWEET’

"It's always a nerve-wracking experience, but, I don't know, we literally left it all on the field with this one,” the actor told the news outlet, in part. “I think we all have a sense of pride.”

"It's a bittersweet quality to it, because this is the last time this gathering of this group of people is gonna be here together,” he added.

The film, which was released Friday and closes the book on the first 11 years of the Marvel Cinematic Universe, ends the yearlong cliffhanger of "Avengers: Infinity War," in which half of the universe turned to dust.

The Associated Press contributed to this report.