Cut a rough oval 12" long and 10" wide from your wooden basing material. Use the oval as a template and cut out the shape of the pool from your foamcore.

To create the banks of the pool, apply a thin line of white glue no more than 1" from the edge of the base. Next, glue your foamcore directly to the wooden base.

Use a pen to draw a smaller pool shape in the centre of the foamcore This shape should be at least 1" from the edge of the base.

Use your craft knife to cut out the shape you have just drawn. This shape should be easy to remove as the glue will hold down only the edges of the foamcore.

To help the pool blend into your gaming board, use your craft knife to bevel the edges of the foam card.

To add the effect of bubbling digestion, cut the polystyrene balls about a third of the way across – so that you’re left with a dome shape. Glue the domes to the pool with white glue.

Make the smaller bubbles by cutting the small wooden balls in half with a pair of modeling clippers. Glue the ball in between the larger polystyrene balls to suggest a build-up of bubbling gastric juices.

Create the half-digested matter by mixing sand, gravel, and white glue. Apply this mix to the pool in patches with an old brush. As the mix dries, gently use your brush to stipple the biomass.

Next, mix up some white glue and talcum powder. Once you have a suitably viscous mix, use an old brush to paint the pool. Make sure you cover the whole surface. Once your first application of talcum and glue is dry, you may want to apply another coat to give a really vile texture to the surface.