Ok my mom is going crazy about this movie

So it's a late night and my mom is thinking about this mystery movie and here are the details she said. She said that it's a black monster and he turns into that creature when he's angry.He has a ex wife with blonde hair and he saves him on a building?? And she also thinks it's a avenger or something. And that creature he turns into kills people but he's a good guy. So that's all I know please let me know in the comments if you know the movie