ElasticEase

As the name says, it represents an easing function that creates an animation that resembles a spring oscillating back and forth until it comes to rest. The Oscillations property can be used to get/set the number of times the target slides back and forth over the animation destination. The Springiness property can be used to define the stiffness of the spring. The smaller the value of Springiness, means a stiffer spring in action.

To demonstrate, let's add the following RadioButton inside the StackPanel to create an animation with ElasticEase, having Oscillations="3" and Springiness="1":

<RadioButton GroupName="AnimationSelector" 
             Content="ElasticEase - EaseInOut" 
             Margin="4"> 
    <RadioButton.Triggers> 
        <EventTrigger RoutedEvent="RadioButton.Checked"> 
            <BeginStoryboard> 
                <Storyboard AutoReverse="True"> 
   ...