Harry Potter Headcanons

full moon

James Potter turning in his homework in under Remus' name that one time he forgot about an assignment after a particularly bad moon, and taking the detention himself.

Minerva McGonagall recognizing James's handwriting and understanding exactly what had happened, and having James spend detention working on a no-credit special project because she knows he loves Transfiguration and can't bear to punish him for taking the fall for his friend.