Andrew, much to my embarrassment, has played several pranks on his Grandad.
I remember the time when Dad came down holding a bar of soap with his false teeth, otherwise known as laughing boy, firmly embedded in it. Dad took it really well and said they needed a good clean.
Dad was always very proud of his pond and took a lot of time and pleasure looking after it and painting his gnomes. Imagine his face when he saw that one had been beheaded - Andrew had found a big stick. Again Dad just laughed.
Another time Dad took the children for a walk with Oscar. Andrew and Oscar made a bolt for home and Grandad had to chase them shouting and waving his walking stick. He said he couldn't remember the last time he had run so fast and he hoped nobody saw him or they wouldn't have believed that he found it hard to walk.