I don't understand why people refer to all spice as K2. In the same way that not all brands of shoes are Nike, not all brands of "spice" are K2. K2 has become a catch-all term for synthetic cannabinoids when it shouldn't be. In addition to that, there is no such thing as a strain of THC. THC is THC, and synthetic cannabinoids are synthetic cannabinoids. While they are both cannabinoids, they are completely different chemicals. Because there are so many different types of synthetic cannabinoids, the effects vary from cannabinoid to cannabinoid. While the one you smoked might have given you a five-minute high and a headache, that shouldn't be used as a description of synthetic cannabinoids in general.