The MOAB Construction Facility is a SupportMonkeycard in Bloons Card Storm, introduced in version 4.0. The player cannot control its attacks manually. Each time the player plays a Large Bloon (not from the Storm), it consumes 1 Ammo to decrease its delay by 1 but take 50 damage. When it runs out of Ammo, it automatically removes itself at the end of the turn.
The general purpose of the MOAB Construction Facility is to speed up Large Bloon spam at the expense of HP and Gold. However, the 50 lost HP is about as much damage as most early-game enemy defenses can do in a single turn, and by the time the player can afford this and Large Bloon spam then they'd have many methods of high damage.
This card seems to be designed with ZOMGs in consideration. However, a maxed MOAB Construction Facility setup is difficult to obtain, and cannot be bought all in one turn (22 Gold, 12 to build 3 of this Factory).
The only 3-delay Large Bloons are Emboldened Bloon and Piñata Bloon, and so a full MOAB Construction Facility setup would essentially convert them to 150 HP face damage, excluding shields, passives of Quincy or Adora, Hero Protection, or ARBITR.
Do not play any Immobile Large Bloons while a MOAB Construction Facility still has remaining ammo, as these Bloons will simply take damage.