It is likely that you know this music even if you never heard the name. Tocatta and Fugue in D Minor has been used in hundreds and possibly even thousands of different movies, video games, and so forth over time. An orchestral version of this piece was done in the Disney movie Fantasia; however, the music was originally written to be played on the organ, as it is here.
Tocatta and Fugue is attributed to Johan Sebastian Bach, but its exact composer is unknown and scholars debate whether or not it was written by Bach or not. They note the relative simplicity of the music, which, of course, is part of what gives it its slightly creepy air.