Razorsale is an iron proto-drake and the 3rd boss in Ulduar. If you've done the Sons of Hodir quest line then you've met Razorscale before and probably didn't know it. When you help Thorim get his mount back you lure the blue proto-drake Veranus to her nest. She gets captured along with Thorim during their confrontation with Loken. Veranus is in fact Razorscale! Loken changed her into the weapon you see now (like a red-neck changes the life of a sheep). Actually the best representation is Veranus is normal Spider-Man while Razorscale is black suit Spider-Man; and Ulduar has a better plot than Spider-Man 3.
The Fight is covered in depth here. She's a tough birdy to take down but she's a fun fight in my book.