She gives herself the body of her dreams (Futa)

Thinking for a minute, Mabel finally decides what to write. "Not like anyone will know what this means if they see it." Putting pen to paper, Mabel writes. 'New Rule: Mabel Pines body will grow into the body of her dreams when she finishes writing this rule. ..and will grow quickly to fit this.'

As she puts the pen down, Mabel moans as her body suddenly starts getting incredibly warm. Standing up, she moves to the mirror. Dumbfounded, she watches as her breasts inflate, her waist narrows, and her hips widen.

"...Damn~." Mabel breaths out as her hands reach up. Only to gasp as a great heat emits from her crotch, and a massive penis shots up from her skirt and lodges itself under her sweater and between her breasts.