In a high-speed blender, combine all of the ingredients and blend until smooth and creamy. Add a few ice cubes, if desired, for a thicker, more ice-cream-like texture. Serve immediately!
If you don't own a high-speed blender, I'd recommend blending the water, avocado and spinach first, until they are completely broken down with no bits or pieces visible. Then, add in the frozen fruit, vanilla and cocoa, and blend again until completely smooth.