The Mother Goose System is a security system built to keep the Wretched Egg under control in Deadman Wonderland.
The Mother Goose System is a security protocol built underneath Deadman Wonderland to keep Shiro's powers as the Wretched Egg supressed, keeping her alternate personality of the Red Man in check. The system was created after the Great Tokyo Earthquake when Shiro unleashed the full magnitude of her powers by Sorae Igarashi, Ganta's mother. It was stated that without the system in check, she would have leveled and sunk all of Japan. It is controlled through a series of blocks called Chorus Blocks that are hidden all throughout the park that emit a low frequency pitch called the Lullaby. The purpose behind it is to keep Shiro's power as the Wretched Egg under control, causing her other persona to be lie dormant.
It is said though that the Chorus Blocks are actually solid blocks of human flesh and tissue taken from Shiro by the pound due to her regenerative abilities. This is why she is the only one that is able to hear the chords of the Lullaby. It is also shown that a special key is needed in order to access it via the powers of a deadman. Sorae made it so that Ganta would be the one who could access the system as Toto finds out about this and tries to access his powers to shut it down. This fails though as Senji is able to stop him.