I think it is a motive.
The musical form that takes one idea and then changes it in some way is theme and variations.
symphonic poem
That would be a melody. You may be thinking of 'motif'.
complete
motive
A motive is a short musical idea.A short musical idea.
A short MUSICAL IDEA.
short musical idea
short musical idea
A motif. It is a short musical idea or phrase that is repeated or developed throughout a composition, forming the basic building block of a musical piece.
As a composer develops a musical idea she may use fragmentation as a way to shorten the musical motive.
Another term that usually refers to a piece of (although it can also refer to a rhythm or a chord progression) is "motif." A motif is a short musical idea-shorter than a phrase-that occurs often in a piece of music. A short melodic idea may also be called a motif, a motive, a cell, or a figure.
A. Prelude
It is called staccato. Hope it helps!
It's actually called a jumbotron screen
A prelude is a short work for piano. it was a short musical form written especially for piano also though in modern times it's has other uses.