Pacilla thought and thought. Then she remembered a story about her muggle aunt. "Professor, awhile back when I was 7, my muggle grandmum told me and my sister a story about my granddad and my aunt, and two muggle uncles. They were going fishing, I think it was like 7 or 8 in the evening when they went out and about half an hour in my aunt thought she had seen a slithery snake like creature rise a little out of the water. Though it was dark and before she had time to tell my granddad, it was gone... Maybe that was sea serpent?"