"This Slug has been developed by Morden's Armies.It moves faster than any Slug of the Regular Army despite its size."-MSD info
The Formor is twice as big as a regular Metal Slug, and it is painted green. The Formor is mostly a smaller version of the Ptolemaic Army's giant Metal Rear, with more maneuverability but less powerful than its giant cousin. Instead of the vulcans, the Formor uses what appears to be autocannons.
Formors first phase will involve it firing its main cannon, autocannons and running over the player. In its second phase, after losing half of its health, it will also try to jump on top of the player.
As this tank attempts to run over the player, its bottom is revealed exposing a weak point, as indicated by a minor explosion every time it gets hit there, allowing the player to deal extra damage.
Due to its low health, Formor can easily be beaten by using the Metal Slug or Shotgun acquired earlier in the level. Moreover, the player can also simply use grenades and the handgun. The Black Hound, Armor Piercer, and Crawler cards are also effective and will make short work of this boss. Defeating Formor again in a fast time will unlock Formor's Card.
- Even though the Formor is much smaller than the Metal Rear, they both seem to have around the same amount of HP.
- Metal Slug Advance's card indicates it's 3 times as big as the normal Metal Slug, though this has been disproved.
- it also appears in Metal Slug Defense as an affordable unit with stars in the 2015 Christmas event.
- It also appears in Metal Slug Attack as an event unit, on the Extra Ops: Boy Memories, its parts can be obtained through the POWs rescued in a random stages... Also, Formor is the only rare unit in Metal Slug Attack which is a boss.
- To date, Formor is the smallest boss in the entire Metal Slug franchise.