The Infinite Improbability Drive is a fictional propulsion system from Douglas Adams' science fiction series, particularly in The Hitchhiker's Guide to the Galaxy. It allows a spacecraft to travel vast distances across the universe by manipulating probability, making highly improbable events occur. When activated, the drive can cause bizarre and unexpected outcomes, such as transforming the ship's surroundings or crew into unusual forms. This whimsical technology highlights the absurdity of the universe and serves as a comedic element in the narrative, showcasing the unpredictable nature of existence in the Hitchhiker's universe.