Dunking

My father was born in this parish, and was a choir boy in this Church. As a child I fed the ducks here, and fished in the moat. But there is something disturbing in this picture. What is it? It is the dunking stone, bottom left, which was used for dunking, a form of corporal punishment. OBSERVATION: But some still use forms of dunking: in military training, for instance, or interrogation. The parish is Welton.