Based on the search results, "What in Hell is Bad" is a mobile game developed by prettybusy, a production company specializing in otome games. The game is set in a secret club located in hell where the Seven Deadly Sins reside as VIP members. Players can touch, tease, and get intimate with these aspects of sin. The game is also a defense-type game where players command the characters and place them on tiles to defend against angels. The game has up to 72 devils available on launch, each with wildly different personalities and physical attributes. The game was released on Google Play store and App Store in October 2023.

It is important to note that the phrase "what in the hell is bad" is not a common phrase or expression in English. It is possible that the phrase is being used as the title of the mobile game and does not have any other meaning.