The EMS-10 Zudah, an experimental mobile suit early in the One Year war. In the trials this thing ran against the Zaku to decide which would be put into production. Though the Zudah here was better, the Zaku was chosen because it didn't explode with pushed too hard. Kind of a draw back there. It was top secret but later on Zeon brought it out and tried to present it as a brand new Mobile suit for propaganda purposes.