Background character

Background characters are cameo characters that appear in a stage that correspond to their home universe (e.g. King Dedede appears in the Super Smash Bros. stage Dream Land). Note that background characters should not be confused with stage hazards (though they sometimes play that role).

In Super Smash Bros.

Peach's Castle

Lakitu can sometimes be seen flying in the background.

Congo Jungle

Necky appears flying in the background.

Dream Land

King Dedede as a background character in Dream Land.

King Dedede and Bronto Burt appear flying in the background.

Mushroom Kingdom

Many classic enemies from Super Mario Bros. are seen in the background.

Planet Zebes

Ridley and Waver sprites ripped directly from Super Metroid can be seen flying around.

Saffron City

Several flying-type Pokémon, including but not limited to Pidgey, Fearow, Moltres (rarely), and Butterfree, fly across the skyline.

Yoshi's Island (SSB)

• Propeller Shy Guys appear in the background.
• A Goonie, in its Yoshi's Story design, occasionally flies in the background.

In Super Smash Bros. Melee

Brinstar

• A Chozo Statue on the main platform comes to life and briefly walks before settling down into its original position. It does not move in Super Smash Bros. for Nintendo 3DS.
• There is a large brain-like organism in the far background that shakes constantly, though it is not based upon any specific creature from the Metroid series.

Fourside

Porky Minch indirectly appears in his helicopter.

Great Bay

After three minutes have passed, the Four Giants appear on the hillside to push the falling Moon back into the sky (This is in reference to the fact that Link had three days to wake said giants and prevent the Moon from falling).

Jungle Japes

Cranky Kong is seen walking back and forth in his cottage, sometimes also rocking in his chair at some points. Flocks of Neckies can also seen in the far background.

Yoshi's Island

A Fishin' Lakitu and a Banzai Bill fly around in the background.

Yoshi's Story

Pak E. Derm can be seen walking behind the scenery.

In Super Smash Bros. Brawl

Regardless of stage and game mode, using Pokémon Trainer will have the Trainer himself stand on a platform in the background. As with the previous games, there are stage-specific background characters as well.

75m

The original Donkey Kong appears on the top of the stage, as in the original game.

Distant Planet

A Red Bulborb occasionally appears in the background. A Cloaking Burrow-nit can also be seen.

Frigate Orpheon

The Parasite Queen, the first boss of Metroid Prime, appears in the background in Frigate Orpheon.

Green Hill Zone

Tails, Knuckles, and Silver can be seen running up and down the shuttle loop.

Tails, Silver, and Knuckles.

Luigi's Mansion

Boos briefly appear from the rubble of the mansion when it collapses.

Pokémon Stadium 2

Electivire, Magnezone, Snorunt, Snover, Drifloon, Hoppip, Skarmory, Cubone, and Dugtrio all appear in the background of the various elemental transformations of the stage.

Shadow Moses Island

Occasionally, Metal Gear REX, Metal Gear RAY, or two GEKKO appear in the background of the stage.

Smashville

Villagers from Animal Crossing appear in the background, depending on actual time of day and date, including K.K. Slider, Tom Nook, and others.

Spear Pillar

Uxie, Azelf, and Mesprit may occasionally appear on the stage at random.

Yoshi's Island (SSBB)

For a third time, Shy Guys appear in the background, with Support Ghosts, Chain Chomps and Goonies also occasionally appearing.

In Super Smash Bros. 4

In Nintendo 3DS

Spirit Train

Toon Link in the Spirit Train stage. Note that this is a pre-release image, as Link cannot appear alongside Spirit Tracks Toon Link in the final game.

• Toon Link, in his Spirit Tracks incarnation, appears as a background character in the Spirit Train stage, where he drives the train.
• When playing the stage as Toon Link or Link, then Alfonzo will drive the train.

Find Mii

A Mii appears in the cage in the background, like the player's Mii in the original game Find Mii. In 3DS, this Mii is the Mii assigned to the player's console. In Ultimate, one of the Miis from the player's system is randomly selected instead.

Tomodachi Life

Miis appear in the background hanging out in the apartments.

Living Room

A few Nintendogs or a cat can appear as background characters in this stage.

Tortimer Island

Kapp'n appears ocasionally in his boat. Also, Leila, Leilani, or Tortimer can appear beside the shop depending on the variant.

Reset Bomb Forest

Prior to the Reset Bomb's landfall, Viridi appears for a moment.

Prism Tower

• Multiple Magnemite appear behind the tower.
• Zapdos, Emolga and Yveltal occasionally appear flying around the tower.
• Helioptile sometimes appears in the bushes on the ground.

Unova Pokémon League

Occasionally, a Milotic, a Shaymin, or a Whimsicott will appear in place of Reshiram or Zekrom.

Mute City (Ω form)

Captain Falcon can be seen riding the Blue Falcon in the background.

In Wii U

Pilotwings

Miis appear on this stage, flying through the sky riding jetpacks. Unlike most Mii appearances, these Miis are pre-modeled and do not use the faces of Miis from the player's system.

Wii Fit Studio

The living Wii Balance Board that is seen upon starting up Wii Fit is seen in the gym. In Ultimate, silhouettes of various people exercising appear as well.

Mario Galaxy

Lubba, along with several other Lumas, appears on Starship Mario in the background.

Mushroom Kingdom U

Nabbit will appear and stuff the fighters in his bag. Kamek will also appear and transform the layout into different courses.

Town and City

• Gracie, Dr. Shrunk, Lloid, and Redd can be seen in the City variation.
• Wendell, Pelly, and Sahara can be seen in the village variation.

Kalos Pokémon League

• Various Dragon-type Pokémon can appear in the background in the Dragonmark Chamber, including Garchomp, Hydreigon, Axew, and Dragonite.
• In the Flood Chamber, Water types Piplup, Wailord, Blastoise, and Clawitzer appear.
• In the Ironworks Chamber, Steel types Klinklang, Steelix, Scizor, and Honedge appear.
• Finally, in the Blazing Chamber, Fire types Infernape, Tepig, Blaziken, and Pyroar appear.

Skyloft

Loftwings can be seen flying around.

Windy Hill Zone

Seven Animal friends (Flicky, Pecky, Picky, Pocky, Cucky, Ricky, and Rocky) from Sonic the Hedgehog can be seen in the background.

Pac-Land

• Mother Fairy appears during the Fairy Land section, where she rewards the fighters with Flying Boots.
• When a round is completed, Ms. Pac-Man can be seen waving to the fighters as they return to Pac-Man's house.

Super Mario Maker

Various Mario objects and enemies sometimes fly by in the background, including Bullet Bills; a Hammer Bro, a Koopa Troopa, a Lakitu flying by in clouds, and a Goomba riding a Koopa Clown Car.

In both

Midgar

Odin, Ifrit, Bahamut ZERO, Leviathan, and Ramuh appear in the background; however, they only appear when summoned and they use moves that affect the stage, such as electrifying the platforms.

Umbra Clock Tower

The angels Affinity and Inspired only appear and fly around in the background of Purgatorio, and occasionally the enormous Fortitudo comes close to the playing field and lets out a powerful roar, shaking the screen.

In Super Smash Bros. Ultimate

New Donk City Hall

The Super Mario Players and Pauline.

The members of The Super Mario Players, including Pauline, appear on floating platforms, and on the ground in front of City Hall. Interacting with the band members causes them to begin performing "Jump Up, Super Star!". Captain Toad and the Odyssey can be seen in the background as well.

Great Plateau Tower

The Old Man from The Legend of Zelda: Breath of the Wild periodically floats onto the stage on his Paraglider.

Moray Towers

Judd and Li'l Judd appear on the stage, indicating who is in the lead by holding up a flag that corresponds to the player's color.

Dracula's Castle

Shadows of Dracula and Kid Dracula appear occasionally, illuminated by flashes of lightning. Other enemies make an appearance, each with an entrance based on how they appeared during their original boss battle in the Castlevania series: the Creature with Flea Man, Mummy, Medusa, Werewolf, Carmilla, and Death.