Ms. Madonna has many knockbacks, short range and an Area Attack with a 100% chance to knockback cats and create a Lv.3 Wave Attack. 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 forward. This is especially important in later stages, where there are powerful backliners that could advance. It is best to defeat her as fast as possible as she can become an annoying support for the enemies.