Download of DockPlayer 1.0 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The program lies within Audio & Video Tools, more precisely Players. The actual developer of this software for Mac is Splash Technologies.
From the developer:
Dock is a minimal audio controller for Spotify that places the spotlight on the beautiful artwork associated with the music you love.
A simple blue bar displays the current progress of each track. On hover, you can access basic playback controls like pause/play, next and previous song. Dock requires Spotify's desktop client.
You may want to check out more Mac applications, such as HALion Player, which might be related to DockPlayer.