Mary-Kate Olsen isn’t taking Spencer Pratt’s insults lying down. After hearing that the Hills star had publicly dissed by calling her a “troll” and referring to her as the “less cute twin,” MK got even with a bit of immature barbing of her own.

The fashion design threw together a t-shirt mocking Spencer.

“She made up a T-shirt with his and Heidi Montag’s faces on it that says ‘Heidi’s Ho,’” an source tells Life & Style. “She texted a picture of the shirt to friends, asking if they wanted to buy one.”

Mary-Kate’s rep denies that such a shirt exist, but friends of the mini-mogul say the star’s got several fashion-forward that are sure to get under Spencer’s skin.

“One of her ideas was to put an ugly photo of them with a caption under Heidi that said, ‘Spencer’s Bitch.’ But she didn’t want to diss Heidi as much as Spencer.”

Even Speidi enemy Lauren Conrad is hoping to get her hot little hands on one of the tops.

The L&S insider says, “Lauren found out about the shirt and wants one…Lauren told her she wants to wear it, so Mary-Kate is going to send her one.”