While designing the Snake & Ladders game, I had to design several shapes of snakes with the same texture. While I could simply design a number of different snakes with similar textures, it would take at least a few hours. Most of the time would be spent copying the textures so that the two snakes don't look different from each other. Instead of designing multiple snakes, I decided to design a straight snake and morph it into different curves using a custom brush.

So, I start by designing a simple snake with some triangular patterns on its back, and two bulged eyes.

Picture of a snake designed in Illustrator.
The "straight" image. 

Then I opened the Brushes panel and dragged the shape to it to define a new custom brush preset. Since I needed to design vertically aligned snakes for the Snakes & Ladders game board, I rotated the shape to face the head up.

Dragging a shape to the Brushes panel to define a custom brush in Illustrator.

Of the available options, I marked the new brush as an Art Brush. Here's how it looks like:

Selecting a brush type for a new custom brush in Illustrator.

From the Brush Scale Options selection, I selected the Stretch to Fit Stroke Length option and clicked on the OK button to confirm my selection. You can play with other options to flip the shape or change its behavior. I picked the options that worked perfectly for my use case.

Selecting the correct Art Brush scale options

The new brush is now available in the Brushes panel. Now from the toolbox, select the Pen tool, and then click on the new brush to start using it.

A new custom brush is now available in the Brushes panel.

To draw a snake, I could simply draw a curved path and then select the new brush, while selecting the path. The brush would automatically draw the snake that followed the curve I just drew.

The new brush follows the curve to make a snake. 

That's, my friends, how I made a dozen snakes within minutes instead of hours. This method is extremely useful if you're creating a sprite animation for similar objects, whose shape needs to transform just a bit in every frame.