Super Paper Mario

Throwing a rubee at her while she's on the ceiling will knock her back down onto the floor.

While Mimi's on the floor, jumping on her head or throwing another rubee will stun her. Hit her again while she's stunned to knock one of her legs off. Repeat until her legs are all gone (how do you walk with one leg anyway)?

Whn she goes on the ceiling, put a bomb under her whn she is in a corner. Once she falls, she'll be dizzy and her head will spin. Jump on her head and she'll loose a leg. Repeat the process until she lost all her legs... or maybe until she has only one leg.

That wil only knock her down after that when she is on the ground jump on her. She will lose a leg. keep doing that untill all her legs gone and then she dies. VICTORY!!!

Trust me that works the best.

NO. I used that process and I beated her, without losing ANY health.

If simply reading these answers doesn't help, try watching this: www.youtube.com/watch?v=ai2-k4a3-ks skip to 6:03 and if you don't want spoilers, then stop as soon as you understand how to beat her. (the video shows the cutscenes the follow beating the boss)

Use princess peach and press down when about to get hit
When she stops attacking, use Thoreau (spelling?) to throw / jumpwith the rubies at her. She will lose a leg and eventually die. Best way, Can't get hit. Works quickly (: