His original furry transformation was an idea that originated with Roy Thomas, with input from Stan Lee, an effort to make the character more visibly striking. He also became more werewolf-like to capitalize on the success of Werewolf by Night.

His eyes were literally stars

Magnanimous and proud

His voice was like a thousand songs

Sung by choirs of heavenly hosts

His gaze pierced through his captors

Without hatred or malice

His voice rang out shrill

As they strapped him to the metal table

He struggled to and fro

Like a brilliant and savage beast

His whimpers: melodious

As they reached for a scalpel

His chest labored wild in fear

Where there had once been wonder

Only a question remained

As they cut him into pieces

The stars went out

One by one

- Vivisection, © Maddy Rain 2017 (via MoxitheFox)