Balloon Mario

Balloon Mario (referred to as Floating Power for Super Mario 64 DS) is a form of Mario first appearing in Super Mario World and later appearing in Super Mario 64 DS. The former appearance requires the player to get a Power Balloon to obtain this form, and the latter requires a Power Flower.

Super Mario World / Super Mario World: Super Mario Advance 2
In Super Mario World, upon collecting a Power Balloon, Mario or Luigi swells up like a balloon, causing him to hover in the air. They will gradually float upwards if not moved by the player, but is capable of moving in any direction for a limited amount of time. During this time, Yoshi cannot be ridden. Mario or Luigi will start to deflate when the item is about to wear off, and once it does, they return to normal size and drop out of the air. The level Tubular in the Special Zone requires the player to continually pick up new Power Balloons to maintain flight while they make their way across the level.

If Mario or Luigi pass through a Giant Gate while under the form, they will gain a bonus Super Mushroom.

In Super Mario World: Super Mario Advance 2, the game music's tempo is slightly decreased while Mario or Luigi is in this form. When the form is about to wear off, a deflating sound plays until they return to normal.

Super Mario 64 DS
The form and its effects returned in Super Mario 64 DS, where, upon picking up a Power Flower, Mario would inflate like a balloon and float. The control scheme for this transformation has been changed somewhat; Mario now gradually floats downwards instead of upwards and has to be kept in the air by tapping the jump button, similar to swimming in 2D Mario games. Once again, he flashes when it is about to wear off and plummets when it does. The player can also automatically end the transformation at any time by ground-pounding. Mario is the only character who is affected this way when he picks up the Power Flower. In this game, the music that plays when Mario turns into Balloon Mario is a slow-paced arrangement of the Wing Mario theme.

Super Mario Maker / Super Mario Maker for Nintendo 3DS
While this form is not usable in Super Mario Maker and Super Mario Maker for Nintendo 3DS, knocking on a Warp Door in the Super Mario World style may cause Weird Mario to appear in this form.

Super Mario Maker 2
Super Mario Maker 2's 3.0.0 update adds the Power Balloon along with Balloon Mario and balloon variants of the other characters, exclusively to the Super Mario World game style. There is a visual difference in the sprites in this form, as the character's pants are now turned yellow and emblazoned with a white "P" (for Toadette, the "P" is on her skirt). The functionality of the Balloon form was also altered, allowing the character to be fully in control of which angle and direction they are floating towards, as opposed to the original game's simple vertical and horizontal mobility. While moving quickly with jump or run, blocks can be activated (Hidden Blocks still can only be hit from below) but there is no way to directly attack enemies. While in the Balloon Mario state, Mario counts as constantly airborne even when on the ground. Balloon Mario is no longer timed, but no longer stacks with the current power-up; if hit, Mario reverts to Super Mario.

Unused sprites indicate that originally, the Buzzy Shell and Spiny Shell could be used by Balloon Mario, with the shell becoming a bubble around him. There are two variants of the former and three of the latter, suggesting the idea went through multiple iterations before being abandoned.

The Weird Mario Easter egg also returns.

Super Mario-kun
Balloon Mario also appears in volume 6 of Super Mario-kun, being featured in a single chapter. Mario, Luigi, and Yoshi are shown with these forms throughout the chapter.

Mario & Luigi: Bowser's Inside Story / Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
In Mario & Luigi: Bowser's Inside Story and its remake, Mario can walk into an air vent and become inflated. Luigi can grab onto Mario, allowing them to jump higher and slowly float down. The brothers learn the skill at Toadley Clinic after they get the second Star Cure, when Dr. Toadley's intern asks them to catch Birdley flying in the clinic.