Twitter popped a poison pill. Here are 3 other companies that did, too.

Twitter’s board of directors voted to take a poison pill to try to prevent Elon Musk from executing a hostile takeover. Also called a shareholders-rights plan, a company engages in a poison pill strategy by diluting the value of the hostile party’s shares by flooding the market with new, discounted stock.

The practice became widely used in the ’80s and ’90s at the height of corporate takeovers, but here are three companies who popped the pill to thwart unwanted bidders in the past decade.

Lee Enterprises

The newspaper chain adopted a poison pill plan late last year after hedge fund Alden Global Capital made an unsolicited offer to buy the company. Alden has been gobbling up newspapers across the country, making deep newsroom cuts in the process. Lee Enterprises has news products in 77 markets in half of the United States, including 12 papers in Nebraska. Alden’s hostile bid came two years after a failed attempt to acquire USA Today publisher Gannett.

Papa John’s

In 2018, the pizza restaurant chain Papa John’s ate a poison pill to prevent ousted founder John Schnatter from taking control of the company. Schnatter owned 30% at the time and the poison pill plan stated that if he bought even 1% more, he’d have to pay twice the value per share to accumulate company stock.

Netflix

Back in 2012, Netflix took the pill just days after investor Carl Icahn acquired 10% of the company. The plan stated that if Icahn or anyone else accumulated more than 10% ownership, other existing shareholders could purchase two shares for the price of one.

Watch “What’s a poison pill?” here.