Metal Slug Wiki
Metal Slug Wiki



The Unknown Alien serves as the final boss of both Metal Slug Mobile 4 and Universal Metal Slug: Tank Conspiracy. Its origins are unknown, but the Rebels are seen possibly attempting to destroy it when the player enters the room.

Boss Synopsis

The Unknown Alien has three attacks. When the alien lifts its head, it will open its mouth and fire a laser. Its stomach can either produce organic, timed bombs or a short-range fireball. Once the alien received enough damage, an eyeball from the top-left corner of the room will open its eyelid and fire various projectiles.

Its weak point is its head. If hit enough times it will die, and the alien's lair will be destroyed.

Trivia

  • The boss room is similar to the Organic Fortress stage from Gradius Gaiden.
  • The boss itself resembles the Gofer in Gradius II and Mother Brain from the Metroid series.
Characters
Heroes Main Series Marco Rossi | Tarma Roving | Eri Kasamoto | Fio Germi | Trevor Spacey | Nadia Cassel | Ralf Jones | Clark Still | Leona Heidern
Spin-Offs Walter Ryan | Tyra Elson | Hero | Gimlet | Red Eye | Tequila
Mobile Roberto Nicola | Nathalie Neo | Alisa Stewart | Helton | Tilde | Nikita | Matilda | Amir | Whip | Heidern
Support Hyakutaro Ichimonji | Rumi Aikawa | Madoka Aikawa | Utan | Navel | Selina | Issenman Tarou | Eris | Hyakumantaro | Pupipi
Villains Main Series Donald Morden | Allen O'Neil | Abul Abbas | Rootmars | Doctor | Avatar of Evil | Invader King
Spin-Offs Allen Jr. | Oguma | Macba | Lt. Wired | Kanan | Hilde Garn
Mobile Unknown Alien | Victor | Ptolemaios | Anubis the Chained | Nanook
Instructors Sophia Greenville | Margaret Southwood | Riviera von Wittenberg | Maryell von Wittenberg | Cynthia Hartnett | Anne
NPC Announcer | POWs | Duke Koudou | Satiko Suzuki | Gerhardt City Civilians | Scott Amundsen Jr. | Miner | Genie of Lamp | Orca | President | Survivors | Fishman | Lumberjack | Sailor | Chinese Soldier
Crossover KOF Team | Battle Cats
Unused Phil Gene | Michiko Nakajima | Angry Man | "Achilles" | "Tabomba"
Metal Slug Attack
Regular Army Associates MS-Alice | Anna Wiese | Midori Schumann | Mello | Rita Lewinsky | Amber | Nikita | Reika Bradford | Louise | Gisee | MS-Heart | Ashley | Rocky | Growl | Jephet | Victoria | Claudia | Kanae | Howell | Phi | Elizabeth Mariani
Metal Device Project Perche | Ami | Molly | Menzel | Ulala | Maggie | Avvio | Quaith | Karen
Rebel Army Associates Rapid | Julia | Chloe | Izabella | Edda | Growth & Cline | Naomi | Alesha | Jane Doe
ACE Abigail | Dion | Romy | Kriemhild | Katalina
"Frozen Brigade" Beatriz | Vicky | Dolores
Blaze Brigade Grazia | Loretta | Norah
Allen Platoon Destrade | Huracan | Conny | Nantes | Padwah
Science Department Vita | Navy | Nova | Emma | Millefie | Sylfie | Fluffy
Arabian Army Shizuka | Aisha
Ptolemaic Army Rebellion Dragunov | Yoshino | Caroline | Veronica | Sisilia | Towa | Simon | Miharu | Chunyan | Owen | Sho | Lucy | Phoebe | Josette | Mizuna | Matilda | Little Lady Black | Svetla | Humphrey | Lithos | Yutong | Tatyana
Cultists Mira D. Genesis | Maria | Damian | Achetto | Sally | Cara | Oao-One | Sorceress
Secret Sect Anastasia IV | Believers | Beecham | Melvina | Anastasia I | Zahara
Space Army Martians Professor "Aionion" | Mars People Neo | Percier | Clone Abby | Clone Betty | Mars People Rangers | Ariadna | Gemini Twins | Halle | Bonny | Clario | Harriot | Code Marionette:Un | Pauline | Leone | Claris | Unsigned | Draco
Invaders Odette | Annette | Lydia | Nowan | Schwarz Metzelei | Fedeln Metzelei | Rillacle | Franke | Teleko | Bloom Metzelei | Odile | Bersek | Geweih Metzelei | Purple King | Barbeln | Biene Goldenes | Swordeist | Drache Goldenes | Eis Monstrum | Ai Agate
Independent Army Amadeus Syndicate White Baby | Alma | Iron Fortress | Valerian Bears | First Baby | Type:Ant-Lion
Red Goblin Society Scotia Amundsen | Red Goblin | Vatn | Jin | Aileen | Elena | Licht | Ichima | Wendy | Bushin Tenzan
Mummy Army Pharaoh | Cleopatra | Hemet | Arsinoe | Hathol | Sharifa | Ramal | Sekhat
Vampires Aswang | Agalia | Sharl | Grace
"World Military Corp." Kelly | Maya | Mirror Mantis
Mirage Circus Cocatrix | Bunny
Independents El Dorado | Elysion | Esther | Teresa | Minerva | Yang Dao | Otto | Yuki Tsuki Hana | Ido
Bosses
Metal Slug Tetsuyuki | Hairbuster Riberts | Tani Oh | Shoe & Karn | Iron Nokana | Hi-Do

Mini-Bata | Allen O'Neil

Metal Slug 2/X The Keesi II / Iron Nokana MK II (X) | Aeshi Nero | Dragon Nosuke | Big Shiee | Hozmi | Rugname

Mosque Artillery | The Keesi II (X) | Karn (X) | Allen O'Neil | Dai-Manji

Metal Slug 3 Huge Hermit | Monoeye UFO | Jupiter King | Sol Dae Rokker | Rootmars

Twin Ohumein-Conga | Monoeyes | Hairbuster Riberts | Hi-Do | Rugname | Fake Rootmars | Clone Incubator

Metal Slug 4 Brave Guerrier | Toschka Dalanue | The Iron | Big John | Sea Satan | Amadeus Mother Computer

Mecha Allen O'Neil

Metal Slug 5 Metal Rear | Shooting Ray | Screamer | Sand Marine | Avatar of Evil

Black Hound | Stone Turtle (unused) | Gaia Elephant | Ptolemaios (unused)

Metal Slug 6 Bull Drill | Iron Sentinel | Brain Robot | Elder Centipede | Invader King

Invader Controller

Metal Slug 7/XX Worm Mecha | Crablops | Destroyed Crablops | Fall Mecha | The Union | Rebel Gigant | Kraken

Scrap Tower | Big Gate

Metal Slug: 1st Mission Rebel VTOL | Rebel Train | Macba | Rebel Zeppelin | Electromagnetic Crane | Weapons Port Boss | Hilde Garn

Facility Elevator | Macba | Rebel Truck

Metal Slug: 2nd Mission Big Bertha | Terrain Carrier | Rebel Reactor | Macba | Rebel Submarine | Tani Oh | Wired | Rebel Airplane | Hilde Garn's Slug | Rocket UFO

Power Generators | Rebel Rocket | Hyakutaro

Metal Slug Advance Formor | Emain Macha | Kaladgolg | The Keesi III | Cabracan

Allen Jr.

Metal Slug 3D Parachuetruck | Mosque Artillery | Spider-Bot | Underground Cruise Missile | Morden's Battleship | Morden's Castle | Allen O'Neil | Lugus | Lieu
Metal Slug Attack Pharaoh's Arc | Ptolemaios | Ball Slug | Great Mother | Mars Gigantalos | K-O3 Coupled Armored Vehicle | Land Blowfish | Cyclobster | Slug Square | Zoni Doloma | Quadro Jumper | Denturion | D-Gu | Fortmeranian | Rock Mole | Giant Copter | Et A Omnis | Vortex | Digger Base | Crusty Legs | Armored Crawler | Queen Big Snail | 7000 Class Locomotive | Riviere Hyll | Metal Fusioner No.223
Mobile games Rocket Control Room | Unknown Alien | Hellfire | Spiderbot | Cyclops | Mega Laser Turret | Mars Battle UFO | M-32 Water Carrier Plane | Kourai | Alien Floating Structure