Starz is adopting a so-called Poison Pill after the media mogul Byron Allen acquired 10.7 percent of the company last week in a surprise deal.

The poison pill, also called a shareholder rights plan, is typically enacted by companies seeking to ward off hostile or unwelcome acquisition efforts. The plan adopted by Starz would kick in if any one shareholder acquired 17.5 percent of more of the company, and would allow for other shareholders to purchase shares in the company at a 50 percent discount, effectively diluting the activist. Typically the plan is meant to force talks with the activist to better understand their motives and intentions.

Allen, through his family office, paid $25 million for the stake in Starz, which was spun off from Lionsgate last year, buying it from former Treasury Secretary Steven Mnuchins investment firm Liberty 77.

Mnuchin had been a major investor in that company, andjoined Lionsgates boardearlier this year. His interest, however, seems to be on the studio, not in the pay-TV and streaming business that Starz is in, hence the sale.

Allen, however, remains a big believer in pay-TV and streaming, owing The Weather Channel, some local broadcast TV stations and streaming platforms like HBCU Go. Starz would fit neatly into those interests, and his family office indicated that he may be an active player.

Consistent with such investment purposes, Allen may engage in communications with, without limitation, one or more shareholders of Starz, management of Starz and/or one or more members of Starzs board of directors and may make suggestions or proposals concerning Starzs operations, prospects, business and financial strategies, strategic transactions, assets and liabilities, business and financing alternatives, the composition of the board of directors and such other matters as Allen may deem relevant to the investment in Starz, his family office wrote.

Starzs poison pill, however, means that if he wants to make a move, he will likely have to talk to the companys board first.