Which bob dylan song destroyed all previous restrictions on a pop single, including length, subject matter, and poetic diction?

"Like a Rolling Stone". It was a breakthrough because it was made in a rock music format in which musician Al Kooper improvised the organ riff that is known in the track. The length at over six minutes and it features a heavy electric sound, thus it destroyed all previous restrictions on a pop single, including length, subject matter, and poetic diction.