This gigantic unit was an ancient weapon that was discovered by Ptolemaic Army. Due to it's gigantic size, it took a long time for them to excavate this weapon from its original place where it was found, and at some point the Ptolemaic War ended before the Ptolemaic Army was able to use it in the war.
Metal Slug 5 (Unused)
It appears in the unused sprites of MS5. It may have been another mini-boss in the Final Mission of Metal Slug 5.
It appears in game with a variant of colors.
It appears as part of the 1.22.0 update, the normal size has been reduced because the unit was too large for the screen. It mostly serves as a damage sponge, slowly moving towards the enemy base and attacking by stomping on enemies. It uses the Hi-Do missiles as its special attack. During development, this unit was named as "The biggest unit" but it has been renamed as Stone Turtle in the release update.
It was introduced in Update 1.0.2. Just like in MSD, its normal size has been reduced as well due to its huge size. It has all the same attacks as well in its MSD counterpart.
- At the beginning of Mission 5 from Metal Slug 5, if the player watches the tower in the background very carefully, the Stone Turtle can be seen being used as the base of the tower.
- In the released Official concept art of the Stone Turtle from Metal Slug Attack's pre-register event, the Stone Turtle was used as a base for the Mammoth Tower. This references to the Hindu belief of a cosmic turtle carrying four elephants on its shell, which in turn carry the Earth on their heads.
- Its form resembles an AT-AT from Star Wars.
- In Metal Slug Defense, Stone Turtle is one of the toughest units in the game, with a total of 50,000 HP at Level 30 and 60,000 at level 40. As a result, the Stone Turtle is the most expensive unit, and tied with Sandmarine for the toughest unit for Ptolemaic Army. and the second highest deploy cost unit in the Ptolemaic Army.
- Stone Turtle's description in MSD explains why this enemy went unused in Metal Slug 5.