Something to make her grow big and strong.

Stacy stares at her mother's altered form in fear as the woman walks towards, scarlet skin covered with blackish goo. "Mom, wha--what happened to you?"

Her mother smiles. "Oh, you'll see, dear. And you will love it." She leans forward, covering Stacy with a mixture of incubi jism and her own milk, and then pulling her daughter in for a filthy kiss. As Stacy begins to moan as the Strain eradicates her mind, her mother shreds the girl's nightdress, leaving her nude. After briefly fondling her daughter, she turns to the three of you. "All right, studs. Do this little bitch like you did me."

"Damn, Ms. Hale, you're nasty," says Mick.

"Call me 'Danielle'," she says to him with a sexy sneer, "and give my little girl that giant cock of yours."

Mick grins at Derek. "Your mom is so cool," he says, striding forward gripping his engorged dick. Derek laughs and follows suit. They manhandle Stacy, positioning the girl so that their immense rods can plunge into her waiting holes. Soon Stacy is taking her brother's cock in her ass while Mick's pistons in and out of her cunt. The infected teen groans in debauched pleasure.

Danielle regards you with eager eyes. "What are you waiting for stud?" she asks. "Make that little bitch do something useful with her mouth." You laugh and **** your dick into Stacy's mouth. The corrupted girl swallows eagerly, taking its meaty length down her throat. Danielle laughs. "Why are you hunks holding back?" she snarls. "Give that little slut everything you have!" With a nod, Mick and Derek slide their tails into her ass and pussy respectively, while you **** your tail into her mouth alongside your cock. Soon the three of you climax into her--Stacy screams in pleasure around your members as you all tear her soul from her. You watch as her skin begins to darken, the transformation to succubus happening swiftly, Stacy's tight barely-legal form shifting into the voluptuous curves of a true hellwhore.

The three of you disentangle yourselves from her, marvelling in her now supernatural beauty. The sexy succubus giggles and turns to Danielle. "Oh, mama," she purrs. "I feel soooo fucking good now!"

"That's what happens when you let Mistress Lilith in," says Danielle, approaching her now soulless daughter. She caresses Stacy with incestuous lust. "All the parts of yourself you didn't need go away, and all the best bits get stronger. You stop giving a shit about right and wrong, and only caring about fucking and pleasure!" Mother and daughter moan and then give each other a decadent kiss. The next portion of the orgy is however, interrupted by a frantic knocking at the door.