"Ma" makes the rules; break them at your own peril.

Universal and Blumhouse have released the trailer for their upcoming horror thriller, which stars Octavia Spencer as a lonely woman who befriends a group of teens. When they ask her to buy some booze, she invites them to her house to party in the basement.

She lays down some strict rules: One of the kids has to stay sober. Don’t curse. Never go upstairs. And call her “Ma.”

When Ma starts to become terrifyingly obsessive, the teens' parties begin to turn into nightmares.

The movie reunites Spencer with director Tate Taylor  ("The Help," "Get On Up"). It's great to see the actress in a lead role and taking on such a different genre from her usual biopics and historical dramas.

"Ma" opens in theaters May 31.