The Super Mushroom in the Mario series makes Mario grow to twice his height so he can break blocks. In Smash Bros. it makes your character bigger and stronger temporarily.
The Poison Mushroom first appeared in Super Mario Bros.: The Lost Levels, where is acted like an enemy, shrinking or defeating Mario. In Smash Bros. it acts like it does in Super Mario Kart, shrinking characters temporarily.
In Super Mario Bros., the Fire Flower gave Mario the ability to throw fireballs. In Smash Bros. the Fire Flower is held and used to shoot a stream of fire that weakens the more it is used.
The Starman grants Mario limited invincibility in the Mario series, allowing him to defeat enemies with a single touch. In Smash Bros. it prevents all attacks from causing damage for its duration. The invincibility music from Super Mario Bros. plays while this item is used.
In Super Mario Bros., kicking a Koopa Troopa shell would cause it to fire off and ricochet off obstacles, knocking out any enemies in its path. It has much the same effect in Smash Bros., damaging anyone it hits.
A creature made of ice that first appeared in Mario Bros. (Arcade), where it would slide along and turn platforms to ice. In Smash Bros. it can be picked up and thrown at players to encase them in a block of ice.
A small, clockwork bomb enemy that first appeared in Super Mario Bros. 2. In Smash Bros. it can be safely picked up and hurled at an opponent before its fuse is lit. Once it's walking, then anybody who touches it will be hurt by the explosion.
A fire enemy from Super Mario World that moved around the edge of platforms. In Smash Bros. it combines aspects of Hothead and Li'l Sparky, its smaller variant, as it will increase in size as it rolls over the terrain and absorbs attacks.
A green block from Super Mario 64 that contained the Metal Cap, transforming Mario into living metal. In Smash Bros., simply picking up the Metal Box will transform your character into metal, making them harder to push about, but also much heavier.
A secret item that appeared in Wrecking Crew that would make it easier to break down walls and allowed Mario to run off the edge of platforms through the air if the button was tapped in the right way. In Smash Bros. it is stronger than the regular Hammer and it also allows you to move through the air. Some Golden Hammers are duds and harmlessly squeak when hitting your enemies. The original Wrecking Crew Power-Up theme will play while this item is in use.
A lightning bolt from the Mario Kart series, where it would shrink all the other players. In Smash Bros. it has the same effect, causing all of your opponents to shrink, making them weaker and easier to hit away.
A banana peel from the Mario Kart series, where it would cause players to skid and spin if they hit it. In Smash Bros. the Banana Peel is a relatively harmless item, causing players who run into it at speed to trip over.
The Hammer from the original Donkey Kong (Arcade). Mario would use this hammer to break barrels and enemies, but it prevented him from jumping or climbing ladders. In Smash Bros. you use the Hammer to smash your enemies away, but you can only use one jump and none of your attacks for its duration. Sometimes the head will drop off, leaving you waving a useless handle. The original Donkey Kong Hammer theme plays while this item is in use.
A bouncy spring that appeared in stage 2 of Donkey Kong Jr, and that has since appeared in a number of Nintendo games. In Smash Bros., the Spring can be picked up and moved, then used as a springy platform for an extra-high jump.
In The Legend of Zelda, collecting a Heart Container would add a Heart to Link's health meter and also refill it. In Smash Bros., the Heart Container reduces your damage by 100 percentage points. The Heart Containers that appear during All-Star Mode, however, remove all damage taken.
The cute Bunny Hood was a popular trade item in Ocarina of Time, and in Majora's Mask it made Link move faster and jump a little higher. In Smash Bros. it acts more like the latter, making any character who wears it move much faster and jump higher.
The Deku Nuts were the first items acquired by Link in Ocarina of Time, causing a brief flash that could damage weaker enemies. In Smash Bros. they will make a character they hit turn dizzy temporarily, and are more effective on aerial enemies.
The Screw Attack item gives Samus a devastating jump attack in the Metroid series, destroying anything in its path. In Smash Bros., this badge item is worn, giving characters the same damaging somersault for its duration.
Kirby's favourite food would restore all of his health in the Kirby series. In Smash Bros. the Maxim Tomato reduces your damage by 50 percentage points.
The Dragoon Warp Star in Kirby Air Ride could only be selected if all the parts had been collected. In Smash Bros. the Dragoon Parts fall down one by one, and characters can fight over them and knock them out of each other. When one character has all three, they fly off in the Dragoon and if they manage to hit an opponent then it's a guaranteed KO.
The Warp Star is Kirby's main form of transportation in the Kirby series, carrying him to new areas. In Smash Bros., the Warp Star flies your character off the top of the screen, then brings them crashing down in a devastating crash. You can steer its landing direction slightly after takeoff.
In Kirby's Dream Land, the Superspicy Curry would give Kirby temporary fire breath, allowing him to blast through blocks and enemies. In Smash Bros., it causes the user to overheat and spit a stream of fire from their mouth as they flail around.
In Kirby's Adventure, the Star Rod was used against the final battle with Nightmare to throw stars to damage him. In Smash Bros. the Star Rod is a normal battering weapon. If it's swung with a Smash Attack, however, it will fire off damaging stars.
The Smart Bombs in Star Fox could be fired into groups of enemies and set off to cause a huge explosion. In Smash Bros., the Smart Bomb sets off a huge explosion that pulls all characters into its center.
In the Pokémon games, the Poké Ball is used to capture wild Pokémon. Before each battle, you throw out your Poké Ball to summon your Pokémon to fight. In Smash Bros., throwing a Poké Ball will cause a random Pokémon from a choice of 30 to appear and unleash an attack.
The friendly Mr. Saturn characters in EarthBound spoke in a strange dialect and proved very popular with fans of the game. In Smash Bros., they simply appear and walk around. They can be picked up and thrown, and while they don't cause a lot of damage, they are good at breaking shields.
The Franklin Badge has appeared in every Mother game where it reflects devastating electric attacks. In Smash Bros., wearing the Franklin Badge protects the wearer from all projectile weapons, reflecting them back.
In Animal Crossing, the Pitfall item could be buried in the ground where it would appear as a tempting item. Unwary visitors would then stumble into it and become stuck in a hole. In Smash Bros., simply throw the Pitfall and it will disappear and any players who stand in that spot will become stuck.
The sea urchin enemies from Clu Clu Land would walk around and puncture the hero, Bubbles, unless blasted with a sonic beam. In Smash Bros., the Unira can be picked up and thrown so long as its spikes are retracted, otherwise it causes massive damage to anyone who touches it.
The stick carried by Lip in Panel Pop. In that game it had no use other than decoration, but in Smash Bros. it causes a flower to sprout on the heads of any characters hit with it, draining health. Hit them repeatedly with Lip's Stick to make the flower bigger.
A standard soccer ball. Hit it with a Smash Attack, however, and it will launch covered in flame, which may be a reference to Super Mario Strikers.
The Super Scope light gun peripheral for the SNES was used to play games such as Yoshi's Safari and BattleClash. In Smash Bros., it can fire a stream of smaller shots or charged up to fire big shots.