Jungle de Ikou!

Jungle de Ikou! is a shamelessly Fan Service-laden three-episode OVA about Natsumi, a 10 year old Japanese girl who gains the power to transform into Mii (May in the dub), a super-powered and super-busty flower spirit, from a perverted old earth spirit named Aham (Ahem in the dub.) Along with her friend Nami, who becomes host to the water spirit Rongo, Natsumi gets into crazy hijinks that culminate in her battling Ongo, an evil demon sealed in a statue her archaeologist father found in New Guinea (who spent the first two episodes as her non-evil Wild Child sidekick).

Licensed in the US by Media Blasters.

This series provides examples of:

 * All Men Are Perverts: When Mii becomes a giant to fight Ongo, she tries to get all the men in the area to run off, finding that her clumsiness as giant is doing as much damage as Ongo, but finds they would rather stay and stare at her even if it means dying. Most notably this occurs with some taking pictures up her skirt just before getting crushed by rubble.
 * Attack of the 50 Foot Whatever: Mii turns into a giantess to battle Ongo.
 * Breast Expansion
 * Cooldown Hug: Mii does this Ongo in the form or Marshmallow Hell.
 * Cute Bruiser: Natsumi easily hoists Takumi into the air and throws him a good few yards away.
 * Dance Magic Dance: All magic works this way in this series.
 * Defeat Means Friendship: Rongo, after Mii (with help from Ongo) defeats her, although somewhat begrudgingly.
 * Dirty Old Man: Aham
 * Fan Service
 * Fan Disservice: Aham's demonstration of Natsumi's Transformation Sequence dance, complete with loving closeups of him fondling his man-boobs.
 * Gag Boobs: Mii
 * The Immodest Orgasm: When Natsumi transforms, she lets out a series of increasingly loud and orgasmic-sounding moans, complete with blushing and falling to her knees. Her opponent even comments, "That's the sleaziest transformation I've ever seen!"
 * Kappei Yamaguchi: Takuma.
 * Limited Wardrobe: This applies to basically all of the characters.
 * Magical Girl: (well, a jungle-esque version of the trope)
 * Megumi Hayashibara: Ongo in both his chibi and monster forms.
 * Nubile Savage
 * Older Alter Ego: Natsumi transforming into Mii.
 * One Winged Angel: Ongo.
 * Sealed Evil in A Can
 * Shorttank. Natsumi.
 * Super Powered Evil Side: Ongo.
 * Tokyo Is the Center of The Universe
 * Tomboy and Girly Girl: Natsumi and Nami; Mii and Rongo.
 * Transformation Sequence
 * Wild Child: Ongo.
 * Wrench Wench: Natsumi demonstrates a frankly bizarre amount of knowledge of American aircraft during the second episode for the sake of an Overly Long Gag.