first time i saw it on gwyndolin's head, i genuenly thought it was a sunlight maggot, and i was like "isn't that the thing that made solaire go mad?" and for the longest time i'd think of the lore implications of gwyndolin wearing a sunlight maggot in his head, until i found out that it was a different thing altogether.
if you think about it, the resemblance of the two could be hinting at another common characteristic: the deceptive behavior of both gwyndolin and the parasite, both creating a fake sun that achieve either the faith or the madness of the decepted one. Those are subtle and interesting things to think about. I love this story and this game