Who Stuck the Gorilla in the Sand?

Overview

The Gorilla has intervened in an argument between daddies at the children's playground. The fathers are unhappy because the Gorilla has inadvertently destroyed the children's sandcastle. One of them has taken revenge by burying the Gorilla in the sand. Who did this? As for Sherlock and Hermione, this sandbox investigation makes them nostalgic for school-yard games.