in Minecraft story mode you can see the wither storm made out of obsidian, you can clearly see this here:
https://www.youtube.com/watch?v=cdfxxxZfbSM&t=120s
maybe make it made out of obsidian with the texture.

change it yourself. texture packs

This isn't actually correct, this is the only occurrence of this happening in the game and I will not be changing the texture for it

I can make a texture pack

Wither storm obsidian.zip
I have made it

Wither storm obsidian.zip I have made it

thank you :Dd;s;dd;;dd; 💀 i really needded it