Here’s the latest potential monkey wrench in Viacom CEO Philippe Dauman’s plan to sell a 49% stake in Paramount PicturesSumner Redstone’s National Amusements is talking to investment bankers about other options “including possibly selling a stake in the film studio or some of its Los Angeles real estate,” Reuters reports, citing unnamed sources.

If true, then it might scare anyone looking to make a deal with Dauman. National Amusements owns 80% of Viacom’s voting shares.

This morning Viacom filed with the SEC bylaws changes that the theater chain wants to make that would complicate a deal involving Paramount. They would require any transaction to be unanimously approved by Viacom’s board — which includes Chairman Emeritus Redstone and his daughter, Shari, who’s President of National Amusements and Vice Chair.

Viacom said the change “may be determined to be invalid and void.” Dauman and director George Abrams say that Redstone, 93, can’t manage his own affairs and is being manipulated by his daughter. If a court agrees, then Sumner Redstone’s control of National Amusements — which has 80% of the votes at CBS as well as Viacom — would be governed by a seven-member trust.

Yesterday, Dauman said that deal he’s working on to sell 49% of Paramount would benefit all investors by adding about $10 a share to Viacom’s stock value. A director who voted to block such a transaction might be challenged for violating his or her fiduciary obligation to serve the interests of all shareholders.

The Redstones might be able to flip the scenario if they make their own deal involving Paramount and see whether other directors, including Dauman, reject it.