Can someone help me in finding a Harry Potter story (pairing are H/Hr)!

I think It's happen in sixth or last year of school. During prof. Mcgonecal class who give a lesson about the animagos transformation to the students, when Harry was trying to turn to his animal form, he got stuck in a half human and half feline predator form, I think it's a jaguar or a black leopard, and I think it's magical too. Harry lost his ability to talk because his form, the headmaster give him some kind of blackboard; so Harry can write on it to let others understand him. Also there was some kind of tournament, it's about student who want to win the prize they have to make a beautiful ice sculpture of their own choice, I don't know what the prize is. I didn't finish the story to the end, and I would like to know what happen after the tournament, and how Harry and Hermione got together.

I read the story a long time ago but I lost it. Can anybody help me!