Don’t mess with Rihanna. The pop star brings out the big guns in the latest trailer for Universal Pictures’ Battleship, her first dramatic big screen role.

“She’s a fighter, she’s a killer,” explains RiRi of her tough character, Navy weapons officer Raikes. “I’m one of the boys. We do everything together. We go on all our missions together.”

As part of her physically-demanding role, she hunts aliens at sea.

“These aliens are thugs,”

adds the singer, who suffered bruises, scrapes, and sore muscles while being trained by real military officers.

The big-budget film co-starring Liam Neeson, Alexander Skarsgard, and Taylor Kitsch sails into theaters May 18, 2012.