The Mixer Brush
In Photoshop you can create heavily customized brushes, but there's one limit to them—they must be saved in grayscale. It's because the program converts various shades of gray to various shades of transparency. But what if you don't care about transparency? What if you want to paint with fully colored... strawberries? It is actually possible!
Note: the trick requires Photoshop in version CS5 or higher.
A Bit More Detail
Do you want to learn more about the power of the Mixer Brush? Make sure to check out my course, How to Use Photoshop's Mixer Brush Tool for Digital Painting!