She had created the charm two years ago as a bizarre birthday present, but it had turned out to be one of his favourite things in the world, second only to her. If she tapped her wrist and muttered the incantation "Creatura Solatium," the little otter would simply swim around as though his skin were water, even dancing across his Dark Mark, and he knew very well that Granger had placed it there intentionally. A little light to break up the darkness.