Psycho Mother is a boss fought in Contra: Hard Corps. In Stage 3, right before entering the room to fight the Computer Hacker, if the player climbs up the wall, he or she will find a mysterious character. He will ask if you want to fight in the arena. If the player answers "Yes", the player will go to an arena where they will fight Simondo Belmont, Psycho Mother and Warp Bomber.
Psycho Mother is a large ghoulish creature that is pushing a baby carriage with weapons. It fights by ramming the carriage against the wall and blasting the player with missile weapons. Its child also rises and attacks the player. Once the child and weapons are defeated the mother will still ram the carriage into the wall. If the player is skilled enough, they can go to a safe zone on the wall and just keep blasting until this boss is toast.