Here is a messy, but great dinosaurs tuff spot.

What you need:

• Plastic dinosaurs;
• Fish tank plastic plants;
• Rocks and pebbles;
• Water, flour and food colouring for the goo (or liquid watercolours);
• Pasta, lentils, semolina for different textures.

To make the goo just mix water, flour and colours to get a pancake batter consistency.