What was the original working title of the arcade game Ms. Pac-Man?

The original working title of the arcade game Ms. Pac-Man was Crazy Otto.

Ms. Pac-Man began as an unauthorized modification of Pac-Man rather than as a completely separate Namco design. General Computer Corporation developed the modification, initially calling it Crazy Otto. Its maze layouts, moving fruit, and character changes distinguished it from the original Pac-Man while retaining the basic dot-eating gameplay.

Midway, Pac-Man's American distributor, acquired the project and transformed it into an official sequel. The game appeared in arcades in 1982 under the name Ms. Pac-Man. Crazy Otto is thus the development name, not the final commercial title. The game is also notable for giving the protagonist a bow and for using several different maze patterns instead of repeating one maze throughout play.