KMH informs me re my previous post ("Listless Films") that there's a name for that quirky girl who helps the listless hero find what Manfred calls his "inner Ffufnagel cactus, which blooms within each and every one of us."
Thank you Astronave Nation.
Here's what I found when I googled the phrase:
"Wild Things: 16 films featuring Manic Pixie Dream Girls"
"In his 'My Year Of Flops: [Elizabethtown: The Bataan Death March of Whimsy]' Nathan Rabin coined the phrase "Manic Pixie Dream Girl" to describe that bubbly, shallow cinematic creature that 'exists solely in the fevered imaginations of sensitive writer-directors to teach broodingly soulful young men to embrace life and its infinite mysteries and adventures.'"
And the poster MPD Girl they choose is exactly who I would choose: Kirsten Dunst. I like Kirsten Dunst (well, my inner Ffufnagel cactus does); but I always wondered, what's she on? Now I know: pixie dust!