Four new synthetic drugs, including one called “Crazy Clown,” were outlawed in Florida this week under an emergency rule filed by state Attorney General Pam Bondi.

Under the emergency rule, these drugs are designated as Schedule I of controlled substances, meaning it is a third-degree felony to “sell, manufacture, deliver or possess with intent to sell, manufacture or deliver” these drugs, WCTV reports. Bondi said she will work with the Florida Legislature to permanently ban these drugs.

Cities and counties throughout South Florida passed bans on synthetic drugs last year. In December 2012, Bondi signed an emergency rule that outlawed 22 new synthetic drugs throughout the state. In 2011, the state legislature banned a number of synthetic drugs. Last year, the legislature banned additional versions of the drugs.

Law enforcement officials and prosecutors around the country are finding it difficult to win convictions against makers of synthetic drugs, who are constantly changing the chemistry of the products to stay one step ahead of the law.

In order to convict a synthetic drug maker, officials must prove the person sold the drug, and that the drug was substantially similar to a specifically banned substance. All a drug maker has to do is make small chemical changes to the products so they are not considered “analogues,” or chemical compounds that are similar to banned drugs.