Checkpoint Flag
Midway Points are like checkpoints in Mario sidescrolling games. If Mario or Luigi loses a life after passing through a Midway Point, he will restart at the Midway Point.
They first appeared in Super Mario Bros. and later in New Super Mario Bros. where they were flags with Mushrooms on them. Not all courses, however, have Midway Points.
The Midway Points in Super Mario World, known as Midway Gates, can turn normal (small) Mario and Luigi into Super Mario and Super Luigi, respectively.
They reappared In New Super Mario Bros Wii. In this game they are represented by a black flag with the Bowser's symbol. When Mario touches them, he receives 1000 points and, if Mario is Small Mario, will become Super Mario.
As seen in some screenshots of Super Mario Galaxy 2, they will reappear in this game with the same appearance in New Super Mario Bros. Wii.[1]