Thanks to the enduring power of reruns, viewers are still traumatized by the senseless death of Susan Biddle Ross, who perished after licking toxic wedding-invitation envelopes purchased by her cheapskate fiancé George Costanza.

But did you know there was a behind-the-scenes story about why Seinfeld exec producer Larry David decided to have the character visited by the Grim Reaper?

Jason Alexander revealed the truth during a Wednesday interview with Howard Stern, telling the King of All Media that the problem was a lack of comedic chemistry between him and actress Heidi Swedberg, who played Susan.

“The actress is this wonderful girl,”; he told Stern. “I love her. She’s a terrific girl.”;

But…

“I couldn’t figure out how to play off of her,”; Alexander admitted. “Her instincts for doing a scene, where the comedy was, and mine, were always misfiring. She would do something, and I would go, OK, I see what she’s going to do, I’ll adjust to her. And then it would change.”;

While Alexander struggled while working with Swedberg, producer Larry David was apparently oblivious.

“I had done three episode with her and Larry [David] calls me up at the beginning of the season, and says, “Good news, I got a great arc for you this season.’ I said, “Oh that’s great, who do I get engaged to?’ He said, “Susan.’ I went, “Oh great, who’s going to play George?'”;

Co-stars Jerry Seinfeld and Julia Louis-Dreyfus thought Alexander was being a prima donna — until they found themselves performing in scenes with the actress and experienced the same struggles.

According to Alexander, after doing a scene with the actress, Seinfeld told him: “You know what? It’s f***ing impossible!”;

However, it was Julia Louis-Dreyfus who planted the seed in Larry David’s mind when, after acting in a scene with Swedberg, complained to her boss, “Don’t you wanna just kill her?”;

His solution: poison envelopes and a sitcom fatality.

“Every time I tell this story I cringe,”; Alexander told Stern, “because Heidi is the sweetest person ever.”;

This isn’t the first time the erstwhile George Costanza has told this story. Here, he relays the events that led to Susan’s fate in an interview with the Archive of American Television: