What is this must be the work of an enemy stand?

"This must be the work of an enemy stand" is a phrase commonly used by the characters in the Japanese manga and anime series, Jojo's Bizarre Adventure. In the series, a stand is a supernatural humanoid entity that represents the character's spirit and gives them unique abilities. The phrase is usually used when a character is faced with a strange or inexplicable situation that seems to be caused by a stand. It suggests that the characters are aware of the existence of stands and their capabilities and can pinpoint their involvement in the situation. The phrase has become popular among fans of the series, and it is often used in memes and other forms of internet culture.