This smoothie is often called a Shrek Shake at our house because it can have some odd colors to it. Nonetheless, everyone from the grown-ups to the baby loves it! It can be made with any kind of berry, and another kind of milk could be substituted as well, but we have a dairy allergy at our house. I have substituted kale for the spinach as well, but kale's strong flavor is a bit harder to mask and it may need a bit of sweetener if you go that route.