DRV! is a CAOS command that represents the creature's highest drive as a number. In Creatures 1, 0 (pain) is given as an answer if no drives are pressing. Mark Ashton notes in the Creatures CAOS Guide that developers can use DRV! in the conditional statement: "DOIF DRIV DRV! GT 128" to test the level of the creature's strongest drive. This command was used in the Wishing Well COB.