Synthetic Marijuana known as "fake weed", common brands include Spice, K2, Mr. Nice Guy. The chemical products mimic the effects of cannabis but without the active ingredient THC. Even though synthetic marijuana can cause hallucinations, these are over-the-counter products and they are marketed as herbal incense or as potpourri. These drugs evade laws because their active ingredients are not regulated. When certain chemicals get banned, new versions emerge to continue the cycle. These chemicals are: JWH-018, JWH-073, HU-210. Some banned versions include: JWH-018, JWH-073, CP-47,497, JWH-200. At least 15 states have banned their use. In addition, the U.S. Navy has a zero tolerance policy on their consumption. 
At the moment, "fake weed" does not show up in drug tests. There are many instances of teenagers going to the hospital after being overcome by severe reactions to these chemicals when smoked.