Default Assist Trophies
|Lakitu||Lakitu appears on the stage and then starts tossing Spinies onto the ground, which damage players on contact. Lakitu can be damaged.||Common|
|Hammer Bro||A Hammer Bro. appears on the stage and throws hammers at opponents. He can jump up and throw them in midair and he can also throw hammers while on the ground.||Semi-Common|
|Petey Piranha||Petey Piranha appears on the stage, and starts spitting goop around, making opponents slip. Petey also jumps around, damaging anyone under him and also plowing them in the ground.||Rare|
|Dixie Kong||Dixie Kong takes a barrel cannon and starts shooting fire blasts at foes, dealing good damage if they are caught in the blast radius.||Uncommon|
|Birdo||Birdo runs and jumps around shooting eggs from its mouth, which damages opponents. Birdo will occassionally shoot a fiery egg which may almost cause a KO to damaged opponents.||Semi-Common|
|Kamek||Kamek pops out of nowhere and starts shooting magic blasts at opponents, causing random effects on them (such as sleeping, stunning, shrinking, flower effect or simply dealing damage with a blast). He can also teleport.||Uncommon|
|Waluigi||Waluigi chases after a selected foe, kicks them onto the ground and finally, he does one final power kick, or hits the player with his racket.||Semi-Common|
|Kat & Ana||Kat and Ana fly in different directions slashing at anybody in front of them, but always cross in the same spot.||Uncommon|
|Ashley||Ashley creates a purple cloud when summoned, which has a damaging area of effect.||Uncommon|
|Nintendog||A Nintendog from the game series Nintendogs briefly appears on the battleground before coming up to the screen and blocking the players' views, causing great distraction.||Common|
|Agitha||Agitha from the Legend of Zelda series releases various butterflies around the stage, and these will start slowing down opponents and pushing them a little. Doesn't do damage.||Semi-Common|
|Midna||Midna will start grabbing opponents with her hair, and then throw them, dealing damage and knockback.||Uncommon|
|Tingle||Tingle simply calls up one of five random effects. These can be helpful (such as a rain of hammers, or giving every fighter a Superspicy Curry status) or a hindrance (such as throwing banana peels, resulting in a slippery ground, creating common occurrences of tripping, or releasing a shower of flowers, causing the camera to zoom in on the summoner. ). One of them has Tingle simply fly away on a group of balloons, not affecting the players.||Uncommon|
|Metroid||A Metroid from the series of the same name will float around the stage, latching onto any players it encounters and sucking their health away, similar to what they do in the Metroid games.||Semi-Common|
|Mother Brain||Mother Brain lands on the stage to attack. In addition to the Rinkas circling around her, she will use the Laser Brain Attack to attack opponents.||Rare|
|Saki Amamiya||Saki Amamiya from Sin and Punishment, will appear, and use his Cannon Sword to shoot and slash his opponents. He can jump and shoot as well.||Uncommon|
|Magnus||Magnus appears on the stage and starts doing leaps around and slashes with his sword.||Semi-Common|
|Phosphora||Phosphora turns into a bolt of lightning and starts flying around the stage at incredible speed, damaging opponents in the air. She always tries to aim at foes.||Uncommon|
|Great Reaper||The Great Reaper summons various Reapettes to attack various opponents at once, after a few seconds of charging, the Great Reaper dashes with his scythe to attack opponents with massive damage.||Rare|
|Knuckle Joe||Knuckle Joe from the Kirby series, will use the Vulcan Jab on all other players, and then finish off with either Smash Punch or Rising Break.||Common|
|Landia||Landia flies to the center of the stage and all of the four heads start spitting fire flames at random directions, with random sizes. The damage dealt depends on the size of the fire ball.||Uncommon|
|Daroach||Daroach uses the Triple Star and unleashes a gigantic laser, continuously damaging those caught in the laser and then freezing them. If they are highly damages, they may get KO'd.||Rare|
|Muddy Mole||Muddy Mole just runs around dropping bombs as he does. The bombs will explode shortly after, they don't do that much damage but still send opponents flying a bit.||Common|
|Starfy||Stafy will perform his spin attack on an opponent if he has the chance. However, fighters can easily attack him and send him flying.||Common|
|Lyn||Lyn charges her sword, then slashes an opposing player with little to no warning and with great power.||Uncommon|
|Marshal||Marshal will start with a a dialogue bubble saying: "Keep your rhythm up!" and will start dancing. Anyone that comes close to him will get distracted (stunned) by the music, putting them into disadvantage.||Semi-Common|
|Dr. Wright||Dr. Wright from Sim City appears and attacks opponents by building large skyscrapers beneath them, sending them flying upwards. There is a one-in-ten chance that Dr. Wright will summon a particularly large skyscraper for even more range and power.||Semi-Common|
|Slippy Toad||Slippy Toad from the Star Fox series will appear on stage and will move quickly across the stage, shooting lasers with his Blaster similarly to Fox, Falco and Wolf. He doesn't do that much damage and he can be damaged as well.||Common|
|Andross||Andross appears floating in the background of a stage, inhales and spits forth a flurry of harmful polygons that damage characters.||Uncommon|
|Prince Sable||Prince Sable from For the Frog the Bell Tolls starts swinging his sword around while jumping. After a few seconds, he turns either into a frog or a snake all of a sudden. If he turns into a frog, he jumps on opponents and makes them trip. If he turns into a snake, he will slide through opponents quickly to bite them and do mild damage.||Uncommon|
|Samurai Goroh||Samurai Goroh from the F-Zero series appears and slashes away at the fighters with his katana. He can jump while slashing horizontally.||Semi-Common|
|Black Shadow||Black Shadow appears and then covers the stage in pure darkness. After that, it goes back to normal, revealing Black Shadow in his vehicle driving at a random opponent, highly damaging them.||Uncommon|
|Takamaru||Takamaru appears and stands in one spot for a while. Then he suddenly starts slashing a random opponent and sends them flying with a final slash.||Uncommon|
|Shantae||Shantae appears and transforms in one of five forms by dancing. If she turns into a monkey, she starts jumping on opponents heads, damaging them and possibly making them trip. If she turns into a spider, she starts shooting spider webs to stun opponents and then slam into them. If she turns into a elephant she will just charge and ram at opponents. If she turns into a harpy, she will grab opponents and fly with them, doing mild damage. After a time she drops them. And finally, if turning into a mermaid she will slap opponents with her tail, dealing good knockback too.||Uncommon|
|Mr. Resetti||Mr. Resetti simply stands in one spot, and lectures the players through a speech bubble. Mr. Resetti also occasionally causes a small explosion when he is furious.||Common|
|Isabelle||Isabelle will start to throw fruits to heal nearby opponents. It appears that Isabelle can heal any character, and not just the one that summoned her.||Common|
|Tom Nook||Tom Nook will start tossing various items at opponents. The damage depends on the items he throws, and he mainly focuses on more damaged opponents.||Semi-Common|
|Jeff||Jeff from EarthBound puts five rockets on the ground, which shoot into the air, homing in on enemies in unpredictable trajectories. Jeff finishes with one large rocket. There is a one-in-five chance that he will summon a second wave of rockets before disappearing.||Uncommon|
|Porky Minch||Porky will start moving across the stage, plowing opponents into the ground with his mechanical spider legs and probably knocking them away.||Rare|
|Wonder Red||Wonder Red from The Wonderful 101, starts slamming opponents with his big fists. If no opponent is near, he just slams the floor, causing shockwaves that also damage opponents.||Uncommon|
|Devil||Devil from Devil's World shifts the stage boundaries. The players will only be able to move within the visible screen and will lose a life if they go off the screen at any point.||Semi-Common|
|Jill & Drill Dozer||Jill from Drill Dozer charges at opponents in her driller. She can jump at them and turn around, but may fall off the stage if she goes too far.||Uncommon|
|Color TV-Game 15||When summoned, the two paddles hit the square back and forth, the square dealing damage to others as it hits them.||Rare|
|Quote||Quote from the Cave Story series simply appears and stands in one spot charging his missile launcher. After that he shoots the missile and it goes directly to the most nearby opponent, causing a gigantic explosion that usually KOs opponents.||Rare|
|Dr. Kawashima||Dr. Kawashima will create numbers that can be attacked to knock them around. When they collide and the numbers add up to ten, they cause an explosion.||Common|
|Elite Beat Agents||The Elite Beat Agents start dancing and singing as music starts playing, any player that comes near their musical zone will get distracted by their music, causing them to make undesired taunts. Doesn't work on the summoner.||Semi-Common|
|Custom Robo||Custom Robo, or MK Ray III, fires bullets from its left gun, and fires missiles from its right hand, as a means of attack.||Uncommon|
Unlockable Assist Trophies
Various Bandits from Sheriff appear on the stage, and they start shooting continuously at opponents as they run across the stage randomly.
To unlock them, the player must play 100 matches in VS. Mode or any related mode.
Sukapon is a rather weak Assist Trophy. He just runs around performing punchs and kicks that do little damage, and he can be damaged as well. However, on rare occassions, he may explode instead of just disappearing, dealing high damage and knockback.
To unlock him, the player must play 200 matches in VS. Mode or any related mode.
An Inkling, either a female one or a male one, from the Splatoon game, will start shooting ink at opponents. With that, opponents not only receive damage but also trip, leaving them vulnerable. Occasionally, they launch a giant blast of ink before disappearing, which mostly does a KO to these in the way.
To unlock them, the player has to clear All-Star Mode with any character on Normal or higher difficulty.
The Duck Hunt Dog will stay quiet in an area and start summoning Wild Gunmen to shoot at different sides. Sometimes the Duck Hunt Dog will also throw an explosive barrel from Hogan's Alley. All this references his moveset from Super Smash Bros. for 3DS / Wii U.
To unlock them, the player has to clear Classic Mode with 20 characters on any difficulty.
|Stanley the Bugman||
Stanley the Bugman appears and starts using his pesticide to slightly damage and push opponents away. He also uses it vertically to attack jumping opponents.
To unlock him, the player must play as Donkey Kong 10 times in VS. Mode or any related mode.
Micaiah uses a magic blast spell upon a random enemy, stunning them and then dealing up to 40% damage. If the opponent is already highly damaged, she KOs them.
To unlock her, the player has to unlock Roy, Robin and Tharja.
|The Eternal Diva||
The Eternal Diva is one of the rarest trophies in the game. When released, she starts singing a beautiful lullaby, healing her summoner almost entirely and stunning the others under the effects of her song for several seconds, putting them into disadvantage. The more damaged they are, the more time they are paralyzed.
To unlock her, the player must unlock Professor Layton.
Nikki from Swapnote is a very common assist trophy. She stands in one spot and starts sending multiple winged swapnotes at random directions, slightly damaging opponents. After that she waves at her summoner and dissapears.
To unlock her, the player must play 15 matches in Swapnote with any character.
R.O.B. appears and starts moving around the stage, shooting lasers randomly that do slight damage. Touching R.O.B. also causes damage and knockback.
To unlock it, the player must unlock Professor Hector.
Melia from the Xenoblade series uses her elemental spells in the battle. She summons Lightning to boost her summoner's speed and strenght for a short time, Blue to bind opponents and finally Fire to incinerate and do great damage on them.
To unlock her, the player must unlock Shulk.
|Shadow the Hedgehog||
Shadow from the Sonic the Hedgehog series uses Chaos Control to slow down the fighters. The summoner can still move normally though.
To unlock him, the player must unlock Sonic.
|Elec Man||Elec Man from the Mega Man series will run around and attack opponents with his Thunder Beam attacks. He uses various projectiles.
To unlock him, the player must unlock Mega Man.
Splash Woman, when released, will summon a giant water wave that will travel across the stage pushing opponents with it. If they are caught and don't exit in time, they may get off the screen and lose a life. The summoner is not affected by the wave.
To unlock her, the player must play as Mega Man 10 times in Vs. Mode or any related mode.
Mallow from Super Mario RPG: Legend of the Seven Stars returns as an assist trophy after a long absence. He uses Star Rain, summoning several shooting stars from the sky. They do decent damage, but some stars do more damage than others, specifically the bigger ones.
To unlock him, the player must unlock Geno.
Moogle from the Final Fantasy series will fly across the stage leaving a magic dust that will heal the fighters. It doesn't only heal its summoner, but opponents as well. However, the summoner is healed slightly more than the others.
To unlock it, the player must unlock Black Mage
|White Mage||When released, White Mage starts floating around and shooting several light blasts with different shapes and move patterns. The light blasts do fire damage if they attack in the air, but if they explode on land and an opponent is caught in the blast, they get stunned.
To unlock her, the player has to unlock Black Mage.
The Ghost gang from the Pac-Man series will appear in their 8-bit form. They will start chasing opponents in various different ways and whenever they touch them they slightly damage them. After damaging an opponent, they switch targets with other ghosts.
To unlock them, the player has to unlock Pac-Man.
Klonoa from the Klonoa series is another character from Namco, the same that created Pac-Man. Klonoa attacks by using his ring, pushing enemies towards himself and then kicking them with a magical blast. Sometimes he simply puts them to sleep, and they take %1 each second they're sleeping.
To unlock him, the player has to unlock Pac-Man as well.
Judgment is a summon from Golden Sun. When summoned, it will fly to the background of the stage, growing into a gigantic size, almost covering the whole background. Then it unleashes blasts of energy at the stage that do extremely high damage on opponents, usually automatically KO'ing them on impact. It's the rarest assist trophy in the game.
To unlock it, the player must unlock Isaac.
DLC Assist Trophies
These Assist Trophies will appear in the game whenever a certain character is downloaded.