One of the biggest names in traditional video games is making its boldest step yet into the fast-growing world of mobile gaming with the multibillion-dollar acquisition of a onetime darling.

Activision Blizzard said late on Monday that it planned to buy King Digital Entertainment, the home of Candy Crush Saga, for about $5.9 billion to help expand its global reach.

At a price tag of $18 a share, King will sell at a discount to the $22.50 a share that it fetched during its initial public offering last year. When the game developer went public, it was greeted with considerable enthusiasm largely on the strength of Candy Crush, where players match three or more matching candies.

King’s hook was in the title’s so-called freemium model, where the game was largely free to play, but additional content or virtual goodies cost real money.