Wow glad I started to read this thread cause that was one of the flavors Ive been thinkin of ordering and im pretty sure i was about to order it from the same place you got it from cause ive only seen that flavor at 1 vendor.The winner:
Blueberry Cinnamon Crumble, and it etched a poly tank. I would have lifted a cat's tail and licked to get the taste out of my mouth. Fortunately, there were no cats handy at the time. I did squeeze the toothpaste tube directly into my mouth, though. It reminded me of Pet Detective.
Anyway worst ever huh? its gotta be DooDooMcPoo, taste like it sounds. Naa, messin, ha. But really the worst ever was a mocha latte which I normally love (just shows you some vendors are vastly superior to others) but in this case tasted like cat urine with a high ammonia content. Really. Reaallllyyy. Yep.