This is the first actual heavy emtal song, Plastic Thunder, released by Bitter Creek in 1968.
https://www.youtube.com/watch?v=IYqvyxK3Qpo
>>74593068
Firstly this just sounds like a pretty bog standard acid rock song from the 60s.
Secondly even if some obscure band invented metal before Sabbath it wouldn't matter because Sabbath had far more influence on music.
>>74593103
This is heavier than the average acid rock from the 60's. If Sabbath's first album can be thought of metal, so can this song because they are very similar.
>>74593068
Sabbath is considered the creators of metal because they down-tuned. Bitter Creek did not.
Of all the proto-Metal bands for me its the Blue Cheer.
https://www.youtube.com/watch?v=FafdwvD6qw0