Forgotten Title MC turns into demon

Hello, I wanted to ask if any of you know the title for this novel where the MC turns into some kind of demon. I think it was a Ox Demon/Devil or something and he had to go to the forest to hide himself and turn himself back into human.

 

大圣传
Legend of the Great Sage

Same work, just that I recalled the CN name, not the EN name.

 

Than

Thank you very much