The Monoeye UFO is the second boss of Metal Slug 3.
This strange artifact of alien origin was created to serve as a beacon for the martians. It has turned nearly every living person around it, including scientists studying it, Rebel soldiers and even survivors of a nearby plane crash into zombies. The beacon causes a power surge that destroyed the floodlights around it, and possibly even caused the plane crash which resulted in civilians joining its undead horde. The artifact is protected by Monoeyes which hover around it, the zombies it creates, and its ability to drop powerful Monoliths that crush anything beneath them.
Before fighting this boss, you must first defeat the Monoeyes that protect it. After that, the boss will show itself. Its only attack is to illuminate its core, summoning Monoliths with alien runes inscribed on them to fall from the sky above your character.
Before landing, a beam of light will shine on the player, indicating a planned landing spot, giving the player a moment's notice to get out of its way. After impact, the Monoliths will slowly sink into the ground. Shooting them will make them sink faster.
However, as the beacon receives more damage, the monoliths will begin to drop faster until it becomes very difficult to dodge.
In Other Games
The Monoeye UFO appears as a boss in Metal Slug Defense in missions 86 and 90. Now it can rapid drop Monoliths at the enemy.
The Monoeye UFO is a boss fought in World 9-5 in both Standard and Elite in the "Attack" mode.
This boss makes its playable debut in the Extra Ops "Clash of the Worlds". Its attacks include dropping one monolith on the enemy's frontline as the standard attack and a compulsive drop as the special attack with six sequentially falling in front of itself. Monoliths can also block projectiles. The Monoeye UFO's spawn method is the same as Aeshi/Assy Nero, moving slowly below the map and then emerging on the enemy's frontline with a huge laser attack.
- The Monoliths may be a reference to the movie 2001: A Space Odyssey with notable allusions to the Ten Commandments of Biblical legend. A few obscure fringe theories even exist in real life connecting the Biblical Ten Commandments to extraterrestrial activity.
- It's possible that whatever process the Monoeye UFO uses to make zombies has been synthesized by the Amadeus Syndicate to create the zombies in Metal Slug 4.
- As seen in the concept art above, the Monoeye UFO has tentacle-like roots below its base buried underground.
- The boss arena has a few blind spots where the Monoliths cannot crush the player. A speedrun tactic is to place a zombified player on one of the leftmost spots and spam the Vomit Laser attack.