Can you name a band that completely changed their sound over time?

I can think of a couple...The Beatles, Radio head, Fleetwood Mac...

The Beatles.

Fleetwood Mac, Chicago (formerly Chicago Transit Authority) Led Zeppelin, Bob Dylan, and more

The Doobie Brothers changed their sound when they had Michael McDonald in the band. When they went back to their original line up, they went back to their original music.

The Cure, but they have thankfully reverted back to older styles.

I'd say most industrial and gothic bands that were going through 80s, 90s and then 2000s. Mid 90s were usually the breaking point. For some early 2000s.

Fleetwood Mac -- from their early days as a great blues band they changed to a pop band with the departure of founder Peter Green.

I just remembered…. ELVIS

David Bowie is the most obvious to me, he was pretty chameleon like in musical styles.

The Black Metal band Darkthrone seemingly changed course after their first 3 or 4 albums, i've heard, those 1st 3 albums are Darkthrone at their purest. They became bland is my understanding.

I am wrong, their debut was just a warm up!! I will always admit being wrong and correct myself :)

Incubus

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[media=https://youtu.be/LTyKOzyqyCM?is=pUTW9rL3o2FtrH7A]

Fleetwood Mac

My Chemical Romance had three good albums, and then their last album was completely different, and I hated it. I still own it because I am a completionist. I don't remember the last time I listened to a song from that last album.