The UFOs are remote-controlled flying saucers used by the martians in Metal Slug.
The remotely controlled spacecrafts are a faster variant of the Mini-UFO, the Martian spacecraft. They attack by firing a laser beam from their bottom, which takes some time to charge but cross the screen at an impressive speed. Unlike the Mini-UFO, they aren't able to warp.
- They are based on the Nazi UFOs.
- In Mission 3 of Metal Slug, when Allen is defeated, sometimes an UFO can be seen. It also can be seen in the game's Final Mission, after Morden explodes the bridge.
|Human||Rebel Infantry | Arabian Infantry | Japanese Infantry | Pirates | Scientists | Ptolemaic Infantry | Natives | Hunters | Future Rebels|
|Undead||Mummies (Mummy Generator) | Dog Mummy | Mutated Soldiers | Zombies | Tar Man | Clones|
|Mutant||Bat | Chowmein-Conga | Ohumein-Conga | Enormous Moray | Jellyfish | Flying Killer | Man Eater | Huge Locust | Sasquatch | Maggot | Big Snail | Giant Caterpillar | Squid | Huge Ivy|
|Alien||Monoeye | Ring Laser Mecha | Hopper Mecha | Mars Mecha | Mars People | Big Eye | UFO | Mini-UFO | Invader Squad | Winged Invader | Flying Parasite | Hunter Walker | Hunter Lord | Scavenger | Crab-Tank | Vanguard | Smasher | Invader UFO | Indestructible UFO | Flying Core|