Butterfly

Butterflies are flying insects that appear in many Mario series, though they typically aren't really important. They usually appear in groups. There are also many creatures that have the similar appearance to a butterfly, such as Tippi from Super Paper Mario (who is occasionally actually classified as a butterfly, though Francis once refers to her as a "digibutterfly").

Super Mario 64
In Super Mario 64, there are a few stages (as well as outside Princess Peach's Castle) where there are butterflies flying around. When Mario punches one of them, one of two things will happen: The butterfly will either turn into a 1-Up Mushroom or become a large metal ball and chase Mario until it hits him, or hits something in its way.

Super Mario Sunshine
In Super Mario Sunshine, Yoshi could eat yellow butterflies to get coins. Blue Butterflies had Blue Coins, and green ones had 1-Up Mushrooms.

Super Mario World 2: Yoshi's Island
Butterflies made their first appearance in Super Mario World 2: Yoshi's Island, where they only appear as part of the scenery and have no major purpose.

Yoshi's Story
In Yoshi's Story, Butterflies reappear as part of the scenery, however numerous Butterfly sub-species such as the Teehee Butterfly and the Power Bee (known as Happiness Butterfly in Japan) appear as edible health restoring creatures.

Super Mario RPG: Legend of the Seven Stars
In Super Mario RPG: Legend of the Seven Stars, Butterflies first appear in the opening with Princess Peach right before she is kidnapped. They later appear as part of the scenery in some areas of the game.

Mario & Luigi: Bowser's Inside Story
In Mario & Luigi: Bowser's Inside Story, a caterpillar-like creature named Durmite appears as a boss twice in the game, however during the second fight it is revealed that her real name is Wisdurm and that she is a actually a legendary Star Sage and after being beaten the second time she turns into a Butterfly. Also in the game a species of Snifit with Butterfly wings appears during battles with Flifits.

Mario Party
Butterflies also made a small appearance in Mario Party; they are shown on the mini-game Ground Pound.

Mario Party 4
They later appear in Mario Party 4 in the mini-game Butterfly Blitz. They have a small but major role; they are worth points when characters catch them. There are three kinds of butterflies that give players points to win; Yellow Butterflies are worth at least one point, Red Butterflies are worth two points, and Blue Butterflies are worth a whopping three points.

Mario Party 8
A Butterfly also made a very brief appearance in the Mario Party 8 mini-game, At the Chomp Wash. When a Chain Chomp sees it, the butterfly causes the Chain Chomp to run into several buckets of paint.