Tesla founder Elon Musk is mocking one of his electric vehicle company's loudest critics, offering Greenlight Capital founder David Einhorn "a small gift of short shorts" for betting against the automaker's shares.

In a letter posted on Twitter and addressed to "Mr. Unicorn," Musk also offered to take Einhorn on a tour of Tesla's facilities, adding that Greenlight's investors "would appreciate you getting smart on Tesla."

The Tesla chief's missive came after Einhorn bashed the company in a letter to investors and on a conference call Thursday. "Tesla has been very creative in its accounting, but, we believe, continues to be structurally unprofitable," he stated, according to a transcript of the call. "We remain short."

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Einhorn didn't immediately respond to a request for comment.

Of late, Einhorn's bet against Tesla has been a losing one for Greenlight. Tesla's shares have shot up more than 50% since the end of June after the company reported an unexpected quarterly profit, an improvement in its results that had Musk gloating. At one point, Tesla's many short-sellers lost $1.5 billion on their bearish bets in a single day.

"It is understandable that you wish to save face with your investors, given the losses you suffered from Tesla's successful third quarter," Musk wrote. "You have our sympathies."

The animosity between Musk and Einhorn is not new. Einhorn in August called on the Tesla CEO to step down after Business Insider reported on an attempt by the company to replace malfunctioning parts in its rooftop solar systems.

"If Tesla wants to save the human species, it should pay more attention to the safety of its own customers. You shouldn't have to be Walmart to have your dangerous solar panels fixed," Einhorn tweeted at the time.

The latest sparring is also not the first time Musk has offered Einhorn, a noted short-seller, some shorts. The investor last summer acknowledged receiving a pair, albeit with what he termed "some manufacturing defects."