Fireworks

Fireworks are explosives that can be found in many Mario games dating back to Super Mario Bros..

Super Mario Bros.
At the end of every level in Super Mario Bros., with the exception of a castle level, fireworks would go off when Mario or Luigi entered the tiny castle (if the last number of the timer is 1, 3, or 6 at the end of the level). If the last number was 1, one firework would go off; if the last number was 3, three fireworks would go off and so forth. Each explosion would award the player with 500 points.

Super Mario Bros.: The Lost Levels
Fireworks appeared again in Super Mario Bros.: The Lost Levels. They worked exactly the same as they did in Super Mario Bros., even awarding the player with the exact same amount of points.

Super Mario World
In Super Mario World, fireworks are seen in the end of the game, after Mario rescues Peach from the clutches of Bowser once again. Four fireworks shoot from the background, the last one being heart-shaped.

Super Mario Bros. Deluxe
In Super Mario Bros. Deluxe, fireworks are seen at the end of the same levels as in the original NES version. However, when the player beats the game, a picture of Mario making a "peace sign" in front of Princess Peach's Castle shows fireworks in its background.

New Super Mario Bros.
In New Super Mario Bros., fireworks were once again used as a fairly common feature of the game. When the remaining time ended in 11,22,33,44,55,66,77,88, or 99, Fireworks would go off behind the castle. It ending in eleven would have one firework, 22 has two, and so on. The original "Level complete" noise would play, and a Mega Mushroom house would appear if it ends in 77, 88, or 99. A 1-UP house for 66, 55, or 44, and an item house for 33, 22, or eleven. They only are for one use, however. Fireworks were worth 4000 points in this game.

New Super Mario Bros. Wii
In New Super Mario Bros. Wii, fireworks are triggered depending on if the game is being played in single-player or multiplayer. In single-player, Mario has to successfully bring a red-capped Toad to the flagpole. The last digit of the remaining time told how many fireworks would be set off. In multiplayer, all players had to reach the flagpole when the last two digits were the same. The number of fireworks was determined by the numbers the last two digits were. In both modes, a Toad House would appear at the beginning of the world depending on the number of fireworks set off. A 1-Up Blast house would appear if 1 or 2 exploded, a Power-Up Panels house for 3-8 fireworks, and a Star house for 9 fireworks.

Super Mario RPG: Legend of the Seven Stars
In Super Mario RPG: Legend of the Seven Stars Fireworks are an item obtained from a Mole Man in Moleville for 500 Coins. They can be traded in for the Shiny Stone in the same town. If Mario purchases one, the fireworks display at the end of the game will be Mushroom-shaped. Purchasing three yields a Fire Flower, while five or more results in a Star.

Luigi's Mansion
If Luigi manages to suck in all 10 ghosts in the Training Room, then fireworks will display and Professor E. Gadd will congratulate the player.

Paper Mario
During the ending of Paper Mario, the procession of parade floats finally ends with Mario and Peach. The float stops, and Mario and Peach get off the float to walk over to Mario's House. There, they view a display of fireworks as part of the ending screen. The fireworks display does not stop until you reset the system.

Mario Golf: Toadstool Tour
In Mario Golf: Toadstool Tour, fireworks are displayed in the background of the last few courses of Peach's Castle Grounds. They are beautifully colored, and can sometimes distract the player.

Mario Party 3
Fireworks frequently display in Mario Party 3. In the end of a Battle Royale or Duel, the winner of the game will be rewarded with fireworks the shape of the character's head. At the end of Story Mode, the Millennium Star will shoot regular fireworks for the character. Finally, at the beginning of the Staff Roll, fireworks the shape of the winning character's head will briefly be seen again.

Mario Party 7
When a player wins a game on a Party Cruise in Mario Party 7, he/she will appear atop Princess Peach's Castle; fireworks are going off in the background.

Donkey Kong Country
In the episode The Kongo Bongo Festival of Lights, the fireworks make an appearance at the end of the episode in which the Kongs get to watch at the end of the festival.

WarioWare: Touched!
In the microgame Big Bang from Wario's stage in WarioWare: Touched!, the objective is to blow up explosives to create fireworks.

Trivia

 * In Animal Crossing, fireworks can be seen in the big lake on the Fourth of July. These fireworks very closely resemble the fireworks found in Mario Golf: Toadstool Tour. The funny thing is that Animal Crossing was released before Mario Golf: Toadstool Tour, making some wonder if the fireworks design was taken from Animal Crossing.
 * In Super Mario Bros., the fireworks were small red dots that sound like a Bullet Bill firing when they went off.