Kylie Jenner rushes to the emergency room, and blames her injury on her older sister Khloé Kardashian -- what could they possibly have been doing?

No biggie. The Keeping Up with the Kardashians reality stars were only having fun, doing a bouncing battle on a trampoline on Tuesday afternoon. It's just that Khloé's playful fighting got a little bit out of control.

Kylie was taken straight to the doctor by her mother Kris Jenner. The 16-year-old took to her Instagram account to post a gloomy black-and-white selfie covering her face with one hand while she was at the hospital. "In the hospital thanks to @khloekardashian. (Look at her page for the reason why)," she captioned the photo. "My mom said 'never thought I would take u [sic] to the doctor for a trampoline accident at this age.'"

"Ps. It was painful taking this photo," she added.

Khloé responded back also via Instagram, saying it was Kylie who hurt herself, posting a snapshot as proof. In the image, a sequence of four photos, the pair is seen bouncing together before Kylie falls back in pain after double bouncing. Although it remains unclear exactly where she hurt herself, it appears that she may have hurt her back as she is holding her back in the picture.

"Kylie this is proof you did it to yourself! Sorry not sorry! Just kidding I am sorry my little bug a boo!! Let the war continue!!!!" Khloé wrote the following caption.

Another photo that the 29-year-old posted was her having a blast with older sister Kim Kardashian, also bouncing on the massive trampoline. While Khloé jumped around in shorts, Kim chose a rather inappropriate outfit for the activity -- she wore a cropped sweater with a high-waisted cream skirt. "Lady and the tramp... You pick who's who," she captioned the snapshot, while Kim reposted the pic with a caption, "Ladies on a tramp."