要实现一个不规则的空心圈圈窗体，你可以使用 C# 的 WinForms 应用程序来实现。以下是一个简单的示例代码：

csharp
Copy code
using System;
using System.Drawing;
using System.Windows.Forms;

public class IrregularForm : Form
{
private Point center;
private int radius = 50;

public IrregularForm()
{
    this.FormBorderStyle = FormBorderStyle.None;
    this.BackColor = Color.Transparent;
    this.TransparencyKey = Color.Transparent;
    this.TopMost = true;
    this.StartPosition = FormStartPosition.Manual;
    this.Bounds = Screen.PrimaryScreen.Bounds;

    this.MouseMove += IrregularForm_MouseMove;
}

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    
    using (Pen pen = new Pen(Color.Red, 2))
    {
        e.Graphics.DrawEllipse(pen, center.X - radius, center.Y - radius, 2 * radius, 2 * radius);
    }
}

private void IrregularForm_MouseMove(object sender, MouseEventArgs e)
{
    center = e.Location;
    Invalidate();
}

[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new IrregularForm());
}

}
这个示例代码创建了一个继承自 Form 的 IrregularForm 类，它是一个无边框、透明背景的窗体。在窗体的 OnPaint 方法中绘制了一个空心圆，而鼠标移动事件则用来更新圆心的位置。通过这种方式，你可以在屏幕上随着鼠标的移动绘制出一个不规则的空心圆。