obscurial forgotten fanfiction

this is kind of a longshot but I'm trying to find a fanfiction that I remember about obscurial harry potter (in this fanfiction I believe that harry is also desi and the Dursleys hide his real name from him) and minerva mcgonagall, actually is the one to find him and wants to take him out of their household. I remember vague details like the fact that he lost control of his magic and there was a lot of ice involved? He also meets Minerva when she's in her cat form. I don't remember anything else and it was on AO3 bit worth a shot