It's been another volatile session for pot stocks broadly.

Day traders could be forgiven for feeling dazed and confused on Monday (for once, it may not have been due to overindulging in their favorite "commodity"). Shares of Tilray, Cronos and other pot stocks fluctuated between gains and losses - while shares of Aphria, another large Canadian pot stock plunged - following two scathing presentations from short sellers during a conference in New York City organized by famed short seller Whitney Tilson.

In what was probably the highlight of the Tilson conference, analysts from Hindenburg Research joined with the founder of Quintessential Capital Management to share their case for shorting Aphria, the fourth largest Toronto-listed pot stock by market cap. During their presentation, the companies accused Aphria of playing a "shell game" with international assets that the analysts argued were largely worthless.

New from us: Aphria—A Shell Game with a Cannabis Business on the Side



Proud to bring you this latest report in conjunction with @QCMFunds who is presenting this joint thesis at @KaseLearning right now. (1/x)https://t.co/DvHDhAqzKN $APHA — Hindenburg Research (@HindenburgRes) December 3, 2018

Next short idea is Tilray $TLRY that’s two cannabis stocks if you’re keeping score at home — Nathaniel E. Baker (@natbaker) December 3, 2018

According to Bloomberg, Leamington, Ontario-based Aphria has raised about C$700 million ($531 million) over the past four years and is the fourth-largest cannabis stock by market value.

In his presentation, AQM founder Gabriel Grego alleged that Aphria has created a mechanism to siphon off investor capital and transfer it to company insiders via "investments" in South America and the Caribbean. According to Grego, Aphria purchased these investments from shell companies controlled by Aphria insiders for "significantly higher" prices than had previously been paid. "Our target price is zero," Grego said.

Grego said Aphria engineered a mechanism to siphon off money to companies held by insiders in South America and the Caribbean to the detriment of shareholders, according to the report. The short seller said Aphria purchased companies in Argentina, Colombia, and Jamaica in September from Scythian Biosciences Inc., now named SOL Global Investments Corp., which had acquired them shortly before at a "significantly lower" price from three Canadian shell companies. The shell companies are linked to Andy DeFrancesco, chairman of Scythian-SOL and adviser to Aphria, according to the report. All three units can be traced back to Delavaco Group, DeFrancesco’s private equity company, according to the report. Their names were changed months before the takeover by Scythian, according to the short-seller report.

A spokesman for Aphria said QCM's allegations were "false and defamatory" and said the company was planning a "comprehensive response."

"Allegations that have been made by the short seller Quintessential Capital in the report that they published this morning are false and defamatory," Tamara Macgregor, Aphria’s vice president of communications, said in an emailed statement. "The company is preparing a comprehensive response to provide shareholders with the facts and is also pursuing all available legal options against Quintessential Capital."

While Aphria experienced the brunt of the selling - falling more than 30% after the AQM-Hindenburg presentation - Tilray, which gained notoriety after its shares went parabolic back in September before erasing all of their gains during the span of one hectic session, briefly sold off after Aristides Capital’s Chris Brown argued that the company's shares are grossly overvalued because the market has so far failed to value the company like a "commodity business".

However, Tilray shares turned positive later in the day following a report in the Financial Times that Marlboro producer Altria was in talks to buy the company.

The report inspired the following humorous comment.

Then they walked when they realized it’s a $10BN company with $30MM in revs? — Hipster (@Hipster_Trader) December 3, 2018

Rounding out the day's pot stock-related news, Reuters reported that Altria was in "early stage" talks to acquire Cronos Group, another Canadian pot producer, as it seeks to diversify its holdings.

Pot stocks have trended lower since Canada legalized recreational cannabis sales back in October. While the sector has largely suffered from a bubble-like influx of capital, concrete reports about a deal where an established beer or tobacco company buys a stake in a cannabis firm - like Constellation brands did with Canopy Growth - could send shares higher.