Animate Ellipse RadiusY, RadiusX

   
     

<Window x:Class="Main"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="" Height="300" Width="300">
  <Grid>
    <Path Stroke="Black" StrokeThickness="1">
      <Path.Data>
        <GeometryGroup>
          <EllipseGeometry x:Name="ellipse" Center="150,150" RadiusX="5" RadiusY="5" />
        </GeometryGroup>
      </Path.Data>
      <Path.Triggers>
        <EventTrigger RoutedEvent="Path.Loaded">
          <BeginStoryboard>
            <Storyboard AutoReverse="True" RepeatBehavior="Forever">
              <ParallelTimeline Storyboard.TargetName="ellipse">
                <DoubleAnimation To="80" Storyboard.TargetProperty="RadiusX" />
                <DoubleAnimation To="80" Storyboard.TargetProperty="RadiusY" />
              </ParallelTimeline>
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Path.Triggers>
    </Path>
  </Grid>
</Window>