Mental Floss teaches me something new every day. Today it was about Alec Guinness and Grace Kelly.  They costarred in 1956′s “The Swan,” and during filming, Guinness was given a tomahawk as a gift from a local Native American. He hid it in Kelly’s bed. Solid prank.

But instead of laughing it off, Kelly said nothing about the prank and kept the tomahawk. One random night, years later, Guinness came home to find it in the sheets of his own bed.

Here’s Mental Floss:

A few more years passed before it was announced that Grace Kelly would be doing a tour of poetry readings in the US with the actor John Westbrook. Guinness didn’t know Westbrook, but arranged for a mutual friend to ask for his help, and then deliver the tomahawk to him, which was placed in Grace’s bed once more. She gave no sign of having found it there, but only asked Westbrook in passing if he had ever met Alec Guinness, to which he could truthfully reply that he hadn’t.

In 1979 the tomahawk reappeared once more, in Guinness’ bed in the Beverly Wilshire hotel, California, after he received an honorary Oscar at the Academy Awards ceremony. Kelly didn’t attend the ceremony, and how the tomahawk found its way back to him on that occasion remains a mystery.

Guinness got the last laugh, burying it in her suitcase under her lingerie in the early ’80s and provoking a “satisfying scream.”

In ’82, Kelly died in a car accident, and the story ends there.