I have smoked K2 off and on for about a year now. In very small doses its fairly similar to weed. I recently bought an off brand called K2 Kryptonite. I took two medium size hits through a bubbler of mine. I was fine for about fifteen minutes and then all hell broke loose. I have done a lot of drugs in my life but dear god!! Two hours stuck in a living nightmare. I lost feeling in my face and hands and couldn't even walk. Ive had a bad trip before on acid but it was nothing like this. With the k2 i didn't see anything that wasn't there but I was stuck in a constant state of fear and horror. I don't know any better way to describe it other than panic, horror, and terror. I threw it away and will never touch it again.