Weird Science - Season 3 - Eps 3: Grampira
Wyatt visits his Grandma in a nursing home and is saddened that she isn't the same old Nana that she used to be. He asks Lisa to give Nana the spirit of a young person, which Lisa does. Nana becomes more spirited, but the new energy is coming from other people- she's sucking the youth out of everyone that she meets. Gary and Wyatt turn into old teens and have to find Nana and return her to the nursing home before they die of old age.
About Weird Science

Title: Weird Science
First Air Date: 1994-03-05
Last Air Date: 1998-07-25
Status: Ended
Rating: 6.682/10 (from 74 votes)
Language: EN
Seasons: 5
Total Episodes: 88
Network: USA Network
Genres: Sci-Fi & Fantasy, Comedy
Production Companies: Universal Television, St. Clare Entertainment, USA Network, Universal Television Entertainment
Synopsis
Gary Wallace, a teenager who dreams of beautiful women and a cheerful life, and his only friend, the shy and geek Wyatt Donnelly, always serve as a target for ridicule and bullying of violent classmates. Once using a computer and mysterious electrical radiation, they manage to bring to life the "woman of their dreams." Her name is Lisa, and she is ready to fulfill the wishes of her creators ...
Cast

Michael Manasseri
Wyatt Donnelly

John Asher
Gary Wallace

Vanessa Angel
Lisa

Lee Tergesen
Chett Donnelly