A-400 is a hostile entity associated with Rooms, a Roblox horror game where players move through increasingly dangerous rooms and try to survive what hunts them. Its scream has circulated as a standalone clip among Roblox players, who recognise it instantly from tense encounters and share it in gameplay highlights, edits and reaction videos. Because the sound is short, loud and unmistakably tied to a sudden attack, it has stayed useful beyond the game itself as a quick shorthand for danger, panic and an unwelcome surprise.