Is spice k2 bad for you?

Yes.

But most would consider that an opinion at this time. No long-term research is available on the specific formula. However, medically speaking, the effects for which spice k2 is used, i.e., hallucinations, are "bad." Any THC derivative has the potential for producing anxiety attacks, some of which may be lingering or long-term, and some research points to THC use as leading to schizophrenia in the long term.