Still, De mortuis nil nisis bonum, so I’ll stop.

“Agnus Dei, qui tollis peccata mundi,” reminds me of a line from “Hansel and Gretel and Ted and Alice; An Opera In One Unnatural Act”, but PDQ Back. Someone pretending to be a monk is singing what he’s pretending is Latin, and sings about “Agnus and her sister Doris Dei”