Carson Block is the founder of the short-seller Muddy Waters Capital.Rick Wilking/ReutersSpeaking at the Sohn Conference in London, Muddy Waters' Carson Block said he was short ELF Beauty.Block's report argued the discount cosmetics company "seems to sell product it does not have."Block referred to import data and conversations with ELF's shipping partners in his report.The notorious short-seller Carson Block has a new target: the discount cosmetics company ELF Beauty.The California-based beauty company "seems to sell product it does not have," Block, the founder of Muddy Waters, said in his report, presented at the Sohn Conference in London on Wednesday.Using import data and referring to conversations Block and his team had with ELF's global shipping partners, the report said Block believed the company had "materially overstated revenue over the past three quarters — possibly by ~$135 million to ~$190 million." Muddy Waters is short the stock, though the size of the position is unclear.Block's report said the firm believed that at the end of last year "ELF management realized its growth narrative was in trouble as its inventory built.""It appears that ELF then began reporting inflated revenue and profits," the report said.