We have no idea what's gotten into Rihanna, but we like it.

She's vacationing in Hawaii and must be bored out of her mind, because all she's been doing (besides smoking weed) is uploading sexy pictures of herself to her Twitter account.

"Haaaa!!! Come tap this @KhloeKardashian," she wrote, while posting a picture of herself in a swimsuit on a treadmill. Another showed her taking a picture of her friend's booty with the hashtag "#CAKE."

Peep the rest above.