SEGA parent company, SEGA Sammy Holdings, is about to close a deal to buy Rovio Entertainment, a company best known for making one of the earliest viral mobile games, Angry Birds.

According to The Wall Street Journal, SEGA is paying $1 billion to buy the Finnish video game company. Rovio and SEGA previously worked together to bring Sonic and the gang to Angry Birds Epic in 2015.

Angry Birds is a now-iconic physics puzzle game that swept the globe in 2009 and resulted in several sequels, spin-offs, tie-ins, and crossovers with known brands like Transformers, Star Wars, and more. Rovio also released an Angry Birds animated series and two feature films, the latter of which grossed over a total of $500 million at the global box office against a $138 million combined budget.

Unfortunately, Angry Birds' success hasn't seemed to have had a positive impact on Rovio's other titles. On the other hand, SEGA hasn't had much success in the mobile market either, which makes this a mutually beneficial acquisition.