Poison Ivy

Poison Ivy is a 1992 thriller starring Drew Barrymore. It was nominated for two film festival awards. The movie was followed by three sequels that were In Name Only.

Sylvie Cooper, played by Sara Gilbert, attends a private school in Los Angeles. She doesn't have many friends until she meets Ivy (Drew Barrymore), a student attending the school on a scholarship. She quickly becomes close friends with Ivy and lets Ivy live in her house. However, Sylvie's friendship isn't enough for Ivy; she wants so much more. And whatever Ivy wants, Ivy gets.

For the Batman villain of the same name, see this page

Tropes used in Poison Ivy include:

Blondes Are Evil: Ivy.
Disney Dog Fight: Between Sylvie and Ivy. Ivy wins by having trained the dog to respond to a food cue.
Dramatic Necklace Removal: a climactic scene involves Ivy half dangling off a building, struggling with the protagonist, when her eye is caught by the meaningful necklace the protagonist is wearing and she makes a grab for it. For one of them, it's a good thing that chain wasn't very strong. For the other one, well, *splat*.
Mercy Kill: Sylvie first meets Ivy when she calmly kills a dog which had been hit by a car to put it out of its misery.
Murder the Hypotenuse: Ivy murders Sylvie's mother so she can have Darryl, Sylvie's father, all to herself.
No Name Given: Drew Barrymore's character is never given a name and is referred to as Ivy by Sylvia because of the ivy-covered cross tattoo on her leg.
Scholarship Student: Ivy attends an exclusive private school on a scholarship and has to maintain a certain GPA to attend the school.
The Vamp: Ivy wants a family, so she decides to murder the heroine's mother and seduce the father in order to achieve her dream.