Ms. Madonna appears to be a female Kang Roo with hair and wearing a coat and high heels. She also holds a folder and a pointer stick. But she has a very different role in enemy's frontlines. She has many knockbacks, short range and an area attack with a 100% chance to knockback cats and create a Lv.3 Shockwave.
This enemy can be dealt with very easily when she's alone, but when supported by heavy hitters such as Teacher Bun Bun or Zang Roo, she can become quite the nuisance.
You can also use cats that are immune to knockback to prevent the enemies front line from moving forwards, this is especialy important in later stages when there are powerful backliners that could advance.