Hulk Hogan's son, Nick Hogan, is suing Bubba The Love Sponge ... alleging the popular radio host's unreleased documentary about the WWE legend infringes on his dad's copyrights and trademarks.
Nick -- acting as a rep for Hulk's estate -- filed the lawsuit on Tuesday in a federal court in Florida ... after Bubba revealed he's going to drop "Video Killed The Radio Star: The Untold Story Of The Hulk Hogan Sex Tape Scandal" later this month.