She makes Shantae's butt grow with every smack.

Rottytops sneaked up to Shantae's lighthouse. It was the dead of night, and the windows were aglow, signifying that someone was inside. In fact, one of the windows had been left open. The zombie girl tiptoed over to it and peered in. On the opposite side of the room, she spotted Shantae. The half-genie was bent over, butt in the air, as she rifled through a wooden chest. Whatever she was looking for, it must have been hard to find, as she was searching hard.

Quietly, Rotty whispered "I wish Shantae's ass would grow whenever something smacked it." The wand began to glow, confirming it heard her command. But did it actually work? There was only one way to find out.

She stuffed the wand in a pocket. Quickly, and with surprising grace, the zombie leapt through the window and sprinted towards Shantae, giving her bum a firm slap and grope before the girl could even turn around. "Ah! Ouch!"

"You had this thing so far up in the air, it was like you were asking for someone to smack it!" smiled Rotty as Shantae turned around to look at her, clearly disgruntled. She didn't notice as her butt swelled out a bit larger and rounder, but Rotty did.

"Rotty! That smarts!" yelled Shantae. "What are you doing here?!"

"Can I not visit a friend just because I miss her?" replied Rotty, putting on her best puppy-dog eyes.

Shantae sighed and softened her expression. "Of course you can, but I'd like some heads-up before you come charging in, at least."

Rotty smiled again. "Where's the fun in that?" She gave Shantae's ass another firm smack, the cheeks growing a bit more.

"Ow! Why do you keep doing that?!" Shantae quickly backed away, worried Rotty might do it again.

"It's so big and round, how can I not?" Rotty shrugged.

Shantae rubbed her sore rear. It felt a bit off, like it was larger than usual. "Look at what you did! Now it's all swollen. I bet it's going to be tender when I sit down now.

"Sorryyyyy." The zombie smiled apologetically. She wasn't sorry at all, though. In fact, she was plotting her follow-up.