In a cocktail stirring glass, dissolve the blue spirulina in a barspoon of water.

Add the rum, stir, and set it aside.

Add the Campari and grenadine to the bottom of a tall serving glass.

Stir to mix, then fill the serving glass with ice.

Gently pour the limeade into the serving glass, being careful to minimize the mixing between the limeade layer and the Campari layer.

Fill the glass with limeade to about an inch below the rim.

Gently float the blue rum on top, pouring through a fine-mesh strainer to remove any undissolved bits of blue spirulina.

Garnish with strawberries and blueberries; for extra flair, garnish with apple slices cut into star shapes and decorated with edible glitter.

Serve with a straw for mixing the layers.