The "will they, won't they" regarding a possible third Left 4 Dead has been around almost as often as that coveted Half-Life 3 speculation. While many Valve fans continue to hold out hope that the company makes it to the number three with literally any of their franchises, a mysterious Left 4 Dead video has appeared on Resetera and YouTube. 

Spotted over on Resetera, a new video has been shared to a YouTube channel that appeared out of nowhere. While obviously this isn't a confirmation of a new game, and could very easily be fan-made, it is worth noting the incredible quality of the video itself. 

Valve has mentioned in the past that they are gearing up to get back into the game-making business and the Left 4 Dead franchise is definitely one of the more beloved series to come from the company. While it's no Half-Life, the co-op horror experience is one that continues to be a standard for this particular genre and fans are more than ready to see that adventure continue. 

With E3 just around the corner and Sony bowing out this year, it's the perfect time for Valve to make their big comeback announcement - perhaps even with this very trailer! Still, until we have more concrete evidence, we're keeping this one firmly in the rumor pile. 

We've reached out to Valve for comment, but likely will have to wait for E3 before anything - if there is anything - to be revealed. 

What do you hope to see from Valve? More Left 4 Dead? Portal 3? Something new entirely? Join in on the conversation by hitting us up over on Twitter @PrimaGames.