Вот так можно, например:

Код AS3:
package
{
import flash.display.Sprite;
public class Drop extends Sprite
{
private var drop_parts:Vector.<Sprite> = null;
private var drop_part:Sprite = null;
public var is_gone:Boolean = false;
public static const COUNT:int = 10;
public function Drop()
{
drop_parts = new <Sprite>[];
for ( var i:int = 0; i < COUNT; i++ )
{
drop_part = new DropClip();
drop_part.alpha = 1 / COUNT;
drop_parts.push( drop_part );
this.addChild( drop_part );
}
}
public function updateDrop():void
{
for ( var i:int = COUNT - 1; i >= 0; i-- )
{
drop_part = drop_parts[ i ];
drop_part.scaleX = drop_part.scaleY *= Math.pow( 0.95, 0.5 * ( i * 0.25 + 1 ) );
}
if ( drop_part.scaleX < 0.01 )
{
is_gone = true;
}
}
}
}

Код AS3:
import flash.display.Sprite;
import flash.display.Shape;
import flash.events.Event;
var drop:Drop = null;
createDrop();
this.addEventListener( Event.ENTER_FRAME, update );
function createDrop()
{
drop = new Drop();
drop.x = 275;
drop.y = 200;
this.addChild( drop );
}
function update( e:Event ):void
{
drop.updateDrop();
if ( drop.is_gone )
{
this.removeChild( drop );
createDrop();
}
}
Архив:
drop.zip