Stay Out of the Basement by R.L. Stine
They're baa-ack! Make way for the bestselling children's series of all time! With a fresh new look, GOOSEBUMPS is set to scare a whole new generation of kids. So reader beware--you're in for a scare! Dr. Brewer is doing a little plant-testing in his basement. Nothing to worry about. Harmless, really. But Margaret and Casey Brewer are worried about their father. Especially when they...meet...some of the plants he is growing down there. Then they notice that their father is developing plantlike tendencies. In fact, he is becoming distinctly weedy-and seedy. Is it just part of their father's "harmless" experiment? Or has the basement turned into a garden of horrors?