Flagpole

Flagpoles are tall flags that appear in most of the Super Mario Bros. games. They first appeared in Super Mario Bros., where they would mark the ending of the level. After reaching one, Mario would run into a castle.

Flagpoles could either have a picture of Bowser on them, or a picture of a skull on them. Also they could come in different colors, black being the most popular. Some come in red, and when a player reaches those, a secret level is unlocked.