I think it was called "Finders". It was either on avengers kink or norsekink where Loki is deaged to a baby when he lands on earth into Tony's home; Tony adopts him and calls him Clark; Loki doesn't remember who he is but still has magic/is super smart/sometimes turns blue.
Any help is appreciated since I'm going crazy trying to find it.
Found by the awesome mremre! It's Finders Keepers by purplemoon3
Thank you :)