It was his idea. He found a dinosaur shaped silicone cake mould in the cupboard, and asked if we could make dinosaur ice in them instead of cake.
Why not! What a clever way to use them. So, I filled up the tray, and then placed in the freezer. Later, we pressed the ice out to reveal dinosaur ice. My son was thrilled. I must see if we have any other shaped silicone trays around the place.