Back in 2016, AT&T announced their intention of buying Time-Warner for $85.4 billion, but this was challenged by the US Justice Department in 2017 as they tried their best to block the acquisition. While this was handled, another company gathered money and was ready to swoop in and buy Time-Warner themselves if the deal would have been stopped.
As you have figured out already (perhaps not too hard considering the headline), this company was Activision Blizzard. This would effectively have more than doubled them in size, and it's not entirely clear why they would have been interested. In an interview with Variety, the Activision Blizzard boss Bobby Kotick revealed the story and said:
"We raised all the capital and were ready to go in the event that AT&T couldn't get the deal done."
He also explained the idea behind this:
"We'd take their IP and turn it into games. They'd take our IP and turn it into film and television, and we'd have an extraordinary company."
Time-Warner (today known as Warner Bros. Discovery) owns an incredible amount of franchises, including all of DC, but also video games like Mortal Kombat, which means they would have become Activision Blizzard brands instead. It's almost hard to imagine how different things would have been in this scenario.
Today things are still looking to change for the company as Microsoft is now trying to buy Activision Blizzard. So far 38 countries have approved this, with the UK being the only ones who declined, which Microsoft will try to appeal. Getting the deal through the US Federal Trade Commission is also expected to be quite the struggle.