StreetPass Mii Plaza

StreetPass Mii Plaza is a pre-installed application on the Nintendo 3DS developed by Nintendo that relies heavily on StreetPass connectivity to play its games. It allows players to create a profile using any Mii that they have made in the Mii Maker, which will be sent to other users via StreetPass when connected, and used to play games. Two games (three after the December 2011 update) which utilize the player's Mii can be played in the Plaza: Puzzle Swap and Find Mii. The game's only unlockables are Nintendo-themed accessories which can be used to dress up the player's Mii, and three dimensional scenes featuring recent Nintendo games or events.

Features
StreetPass Mii Plaza allows the creation of a profile that players can customize with their personal information, which is sent to other users upon connecting via StreetPass. This information includes a Mii, which is used as a player character while in the Plaza, a greeting, a birthday, the 3DS' registered location and minor details such as a favorite hobby or dream. Players can choose to make some of this information private if they wish, and can change the information in the Settings sub-menu at any time. As long as the player has the wireless communications switch turned on, StreetPass enabled, and the system closed, the data is transferred between any wireless-enabled 3DS system within range. A notification light on the 3DS turns green to indicate when another 3DS has been detected, even when the software is closed.

StreetPass Plaza is the location where the player's Mii resides. The Plaza is lush with green lawn and small plants, and features a yellow arch adorned with a grass root as its front entrance. Initially it begins empty and the music begins quiet, but as additional Miis are invited into the plaza via StreetPass and online games such as Mario Kart 7 or Mario Tennis Open, the plaza grows, and the music becomes more dynamic. Upon opening the software after a connection has been made, the front gate of the Plaza is shown with the player's Mii greeting any new Miis that have been encountered while the system was closed, before inviting each to take residence in the plaza and play Find Mii and Puzzle Swap with them.

The player is given the option of playing two games (three games after the December 2011 update) to unlock accessories and 3D images related to various Nintendo series, by using either Miis obtained by StreetPass or Play Coins. After the December 2011 update, additional features were introduced, including a slideshow for completed Puzzle Swap panels, a world map which shows locations that differ to the player's, an achievements list, and a music player for listening to the application's various tracks.

Puzzle Swap
Puzzle Swap features various different puzzles that the player can complete. Players are given one piece to start off with, and more can be obtained by StreetPassing with other people. After StreetPassing with someone, the player is then entitled to take a puzzle piece from them (and vice versa) and add it to their collection. If another player does not have any new pieces, nothing is gained. Players can also spend two Play Coins to buy a random puzzle piece to any incomplete puzzle they have. However, the puzzle piece may be a copy of any earlier acquired pieces, and will be of no use. Once a puzzle is completed, a three-dimensional image of the puzzle can then be viewed.

While the initial puzzles consisted of fifteen pieces, the December 2011 update included several puzzles with either twenty-four or forty pieces, as well as the ability to receive new puzzles through SpotPass. Additionally, the four center-most pieces in the twenty-four piece puzzles and the eight center most pieces in the forty piece puzzles are pink. These pink pieces cannot be purchased with Play Coins, and can only be obtained by StreetPassing other people who have obtained them.

Mario-themed Puzzle Swap Panels

 * Mario and Bowser (15 pieces)
 * Super Mario Galaxy 2 (15 pieces)
 * New Super Mario Bros. Wii (15 pieces)
 * Super Mario 3D Land (40 pieces)
 * Mario Kart 7 (40 pieces)
 * Donkey Kong Country Returns (24 pieces)
 * Mario Tennis Open (40 pieces)
 * New Super Mario Bros. 2 (40 pieces)
 * Luigi's Mansion: Dark Moon (40 pieces)
 * New Super Luigi U (40 pieces)
 * Heroines (features Peach, Pauline, Rosalina and Zelda) (40 Pieces)
 * Mario & Luigi: Dream Team (40 pieces, only in Europe and Japan)

Find Mii
In Find Mii (called StreetPass Quest outside of North America), Miis are utilized to fight their way through several enemy-filled rooms to free the player's Mii from imprisonment. Mario-themed accessories such as character caps can be obtained and later be used to dress up the Miis. When another 3DS is detected, its profile Mii will join in on the game. Players can also hire a wandering hero for two Play Coins, with a limit of up to ten in a single party. However, these heroes are usually very weak (Level 1 or 2) and take the appearance of a dog or a cat depending on the players' preference for cats or dogs which can be adjusted in the Settings menu.

A sequel to Find Mii, known as Find Mii II (StreetPass Quest II outside of North America) was made available in the December 2011 system update. It is similar to the original, but features tougher challenges. It can only be played once the first Find Mii game has been cleared two times.

Enemies
In Find Mii and Find Mii II, the player has to fight through several enemies in order to save their Mii. The following are the lists of enemies encountered during the quests:

Find Mii

 * Ghost: The yellow ghost which is also the main ghost, easy to defeat.
 * Blue Ghost: A blue version of the main ghost with a curl near it's head, they are harder to defeat.
 * Blood Ghost: A bigger version of a normal ghost with a more menacing look and higher health.
 * Armored Ghost: A suit of armor with eyes inside the helmet, these ghosts are like normal ghosts but low leveled warriors are not a good choice for these ghosts.
 * Armored Demon: A bigger blue version of Armored Ghosts, they are still unable to be defeated by low ranked warriors, but high leveled shouldn't have a hard time with them.
 * Armored Fiend: The final normal ghost of the game only encountered at the top of Mirage Tower, this ghost guards the player's Mii and must be defeated, like every other armored ghost, this ghost will be difficult to defeat with low ranked warriors.
 * Ultimate Ghost: The final boss of the game encountered after defeating the Armored Fiend, this purple ghost takes several hits to actually defeat, but teams of different ranked warriors will defeat the ghost. It is also the second boss of the last stage in Find Mii II.

Find Mii II

 * Yellow Slime: A gelatin like ghost that is the main ghost of this game, they get bigger with each hit, but are extremely weak.
 * Wandering Mummy: A mummy ghost, they have the ability to scare the first hero in line when first encountered.
 * Reaper Cadet: A skeleton ghost, they act like Armored Ghosts, as Level 1 heroes can't hurt them.
 * Iron Golem: The ghost that guards the Princess, they cannot be hurt by Level 1 or 2 heroes.
 * Roaming Mummy: A bigger dark blue version of the Wandering Mummy, they can still scare heroes.
 * Marauding Mummy: A red Roaming Mummy with spikes on its head, they are usually teamed with Roaming Mummies.
 * Reaper Captain: A palette swap of a Reaper Cadet, they retain the same attacks and defense against low leveled heroes.
 * Armored Archfiend: A massive Armored Ghost, teamed heroes can take him out easily.

Magic
In Find Mii and Find Mii II, each hero has a different magic spell. The magic's effect depends on the hero's shirt colour. In Find Mii II, Combo Magic can be used with heroes of the same shirt color. Certain enemies will also use magic for defence. Magic can also be used to remove hazards before entering a room. This is a list of all magic performed in the game.
 * Red: A flame-based attack that hits all enemies in a room. It is effective against Blue ghosts and mummies, and is resisted by Blood ghosts. When used as combo magic, the attack is stronger and can be used to thaw a frozen room.
 * Blue: An attack that douses the enemy in water. It is effective against Blood ghosts and resisted by Blue ghosts. When used as combo magic, the attack is more powerful and can be used to cool a fiery room.
 * Light Blue: An ice based attack that freezes all enemies in a room. Frozen enemies cannot move, and heroes may attack until the enemy thaws. Combo magic increases the time enemies take to thaw out.
 * Green: Doubles the level of the next hero in line (Maximum level: 7). When used as combo magic it maximises the level of the next hero in line.
 * Light Green: Puts all enemies to sleep. Similar to the effects of Light Blue Magic, sleeping enemies cannot move and heroes may attack until the effect wears off. Like Light Blue Magic, when used as a combo it increases the time enemies take to wake up.
 * Purple: Poisons all enemies in a room. Poisoned enemies lose 1 HP after the end of each turn. When used as combo magic, enemies lose 2 HP at the end of each turn.
 * Yellow: Whirls up a sandstorm. This decreases the accuracy of all heroes; however it may give them an extra chance to attack if the enemy rubs its eyes. When used as combo Magic a stronger sandstorm can be summoned and can be used to dispel poisonous gas in a room (such as the room found before the castle).
 * Orange: A room effect that invigorates all heroes. Each hero attacks 4 times instead of 3 while the spell is in effect. Combo magic gives each hero 5 attacks instead of 3.
 * Pink: A room effect that makes heroes feel daring. This greatly decreases the accuracy of all heroes, however all hits become critical hits while the spell is in effect. When used as combo magic, there is no accuracy lost.
 * Brown: Summons a bunny to fight. The bunny's level will be less than or equal to the level of the hero who summoned it. When used as combo magic, the bunny's level will be equal to the team's combined level (Maximum level: 7).
 * White: Used to light up a dark room. Reapers take double damage while the room is bright.
 * Black: Darkens a dazzling room. Golems take double damage while the room is darkened.

Enemy magic
In Find Mii II, some enemies use exclusive magic to defend themselves. Gases are used before the fight begins, and can be dispelled by a Dispelling Draught while normal magic can be removed by a Bottled Barrier.
 * Mirage Magic: Used only by Blue Ghosts in Find Mii II. Creates an illusion to evade attacks. The illusion is still affected by magic, and is broken with one sword hit. However, the hero leaves if it hits an illusion.
 * Healing Magic: Used by Roaming Mummies and Reaper Commanders. It heals another enemy's HP.
 * Fortifying Magic: Used by Diamond Golems and the Armored Archfiend to increase defense. The effects can be removed with a Bottled Barrier.
 * Reviving Magic: Only used by the Reaper General. It completely revives a fallen enemy.
 * Barrier Gas: Makes it impossible to use magic while in effect.
 * Curse Gas: While in effect, there is a chance that a hero may lose it's entire turn before attacking.
 * Level-Down Gas: Decreases each hero's level by 1 while in effect. Level 1 heroes are unaffected.

Potions
Also exclusive to Find Mii II, potions can be bought in exchange for Play Coins.
 * Vial of Valour (8 Play Coins): Calls back any heroes who had failed to defeat the monster.
 * Power Potion (20 Play Coins): Boosts the level of the next heroes in line, similar to Green magic.
 * Dispelling Draught (2 Play Coins): Removes gas created by enemies.
 * Bottled Barrier (2 Play Coins): Removes magic created by enemies.

List of Mario-themed hats

 * Mario's Cap
 * Luigi's Cap
 * Toad Hat
 * Bowser Hat
 * Yoshi Hat
 * Yellow Yoshi Hat
 * Light Blue Yoshi Hat
 * Pink Yoshi Hat
 * Piranha Plant
 * Warp Pipe Hat
 * Boo Hat
 * Shy Guy's Mask
 * Donkey Kong Hat
 * Peach's Crown
 * Daisy's Crown
 * Chain Chomp Hat
 * Wario's Cap
 * Waluigi's Cap
 * ? Block Hat
 * Penguin Hat
 * Blooper Hat
 * NES Hat
 * Famicom Hat

Exchange Booth Hats (Japan and Europe only)

 * Pixel Mario Hat
 * Super Mushroom Hat
 * 1-Up Mushroom Hat
 * Fire Flower Hat
 * Super Star Hat
 * Donkey Kong Costume
 * Diddy Kong Hat
 * Barrel Hat
 * Green Shell Hat
 * Red Shell Hat
 * Mario Costume
 * Luigi Costume
 * Goomba Hat
 * Spiny Hat
 * Lakitu Hat
 * Cheep Cheep Hat
 * Yoshi Costume
 * Yoshi's Egg Hat
 * Peach's Castle Hat