Pupils at Upper Beeding Primary School had a shock when they found their classrooms had been invaded while they were out for their lunchtime break.
Tables and chairs were overturned, uniform was scattered about and bags were strewn over the floor.
A letter explained all and a map gave clues for a quest the children had to complete.
Mrs Debbie Gilpin, key stage one leader, said: “A special visitor had left something for them to look after. The letter contained clues, which the children followed using the map, undertaking a quest to find what had been hidden in school for them.
“It was very exciting when we found three huge eggs at the end of our playing field. The children carefully handled the eggs, thinking about what it looked like, felt like, smelt like and what sounds they could hear from inside the egg.
“Each class will now look after an egg to see what might hatch and therefore identify who left them for the children to find.”