What is flakka?

NEW YORK (FOX 5 NEWS) - A designer street drug called flakka, which looks like crystals, is similar to so-called bath salts and can cause psychotic behavior.

Police in Florida say that, one minute, Austin Harrouff, a 19-year-old Florida State University student, was having dinner with his family at a restaurant. Suddenly, he became agitated and stormed off. Forty-five minutes later, Harrouff stabbed a couple to death at their home, police said. He had never met them. When police arrived, they found Harrouff biting one victim's face. Cops had to pull the teenager off the victim. Authorities said Harrouff was "exhibiting abnormal levels of strength.

That is a side effect of the designer street drug called flakka.

Dr. Robert Glatter is an emergency physician at Lenox Hill Hospital. He said the drug can cause psychotic behavior and hallucinations.

In April, a Florida man got impaled on a 9-foot fence after trying to climb it. Another man was caught on video trying to break into the Fort Lauderdale police station.

Dr. Glatter said flakka can make the user feel superman. He said a user can smoke or inject it and that it is very addictive. Sometimes it takes months of rehab to get clean.