Natasha Henstridge is Sil, an incredibly enticing government manufactured human-alien hybrid who discards men after sex if they don't possess the perfect combination of DNA. So yes, she's like most women you've dated, but instead of dumping your disappointing ass post-coitus, she'll murder you.
Henstridge is shamelessly naked for a slew of scenes throughout the flick, but our favorite is when she thumps an overeager Alfred Molina and freaks him out with talk of being insta-knocked-up: "Don't you believe me? Feel!" [SPOILER ALERT] The good news is, she sprouts claws from her back shortly after, and her still-grinning suitor hears no more (because she kills him).