Marching Milde

"Yoshi! Oh dear . . . Well, Marching Milde will pound you to bits!!"

- Kamek

Marching Milde is a giant Milde appearing in Super Mario World 2: Yoshi's Island and its remake, Yoshi's Island: Super Mario Advance 3. She is the mid-boss of World 4, encountered at the end of Marching Milde's Fort by Yellow Yoshi.

Description
Like a regular Milde, Marching Milde does not attack, instead simply walking left and right inside her large chamber, hurting Yoshi if he touches her from any other side than from above. As is the case with Puchipuchi L, jumping on Marching Milde simply causes the Yoshi to bounce off without doing any damage. To defeat this boss, the player must instead Ground Pound on top of Marching Milde to make her split apart into two smaller versions of herself, which are large versions of Puchipuchi L. Employing the same strategy against the large Puchipuchi L makes them split into regular-sized Puchipuchi L, which in turn split into Mildes upon being Ground Pounded. Once every Milde has been destroyed or eaten, the boss is defeated; this makes Marching Milde the only boss in the game that can be defeated by eating them.

Super Mario World 2: Yoshi's Island

 * Official Nintendo Player's Guide: With her mile-wide smile and easygoing gait, Milde is one of the mellowest adversaries Yoshi will encounter on his journey. Hit her with an egg and she'll barely shrug. You'll have to split her personality by pounding her head. She has good reason to be laid back, for few intruders ever make it to the inner sanctum of her caste.
 * Shogakukan guide: 特大サイズのプチプチくん. ヒップドロップをするたびに分裂して、だんだん小さくなる. (An oversized Milde. It splits and gets smaller and smaller with each Hip Drop.)

Yoshi's Island: Super Mario Advance 3
(A big Milde, boss of World 4-4. Every time you Hip Drop them, they split up; the third time they split up, they turn into a regular Milde, so you have to defeat all of them.)
 * Shogakukan guide: でっかいプチプチくんで、ワールド4-4のボス. ヒップドロップするたびに分裂する. 3回めの分裂でふつうのプチプチくんになるので、すべて倒そう.

Trivia

 * Marching Milde vaguely resembles Kirby - both are pink, spherical creatures with red feet and reddish cheeks.