It only took a moment, just the length of time for what Klaus assumed would be blood to wash over his taste buds. He immediately knew something was wrong, but by then it was too late. Ripping away from his would-be victim, Klaus took a shocked step backward. A hand came up to his throat, clutching there as he gargled and choked. The fear of death wasn't there, Klaus still remained confident in his immortality here - there was no white oak or anything of the sort to tie him to the idea of death. However, he still couldn't help the flash of panic at the unknown and that unavoidable knee-jerk need to breath. Even after decades upon decades, his body still recoiled and fought whenever breath was denied - regardless of that fact it was unnecessary.
The fear was short-lived because anger quickly replaced it. Only a handful of frenzied seconds passed where Klaus let the shock rule him. He recovered and lunged forward again, a hand going for the woman's throat. Whatever she'd done, it felt like her blood - or whatever this substitute could be deemed - was alive within him, roiling in his throat.
In all his years, he'd never experienced anything quite like this. Of all the absurdities and impossibilities life continued to throw at him, Klaus had never had something like this happen. Once he could breathe again and his rage at being tricked subsided, he was sure he'd feel intrigued. But there was little Klaus hated more than being thrown off his game and bested.