With throbbing lights and crowds of kids, privately promoted events known as "glow" parties are quickly becoming the go-to parties for teens across the country.

The parties are billed as safe and alcohol-free events for kids as young as 16.

In a new warning, however, officials say the parties, which come with up to a $40 entry fee, are not always just about music and dancing.

"Molly is a drug we have seen being available at many of these 'glow' parties," Angelo Valente, executive director of the Partnership for a Drug-Free New Jersey, told ABC News.

Molly is a form of Ecstasy that has been linked to overdoses and is mentioned frequently in pop culture and music. Molly, short for molecule, is supposed to be the purest form of MDMA, the main ingredient in Ecstasy.

"It raises your body temperature, your heart rate goes up, your blood pressure goes up, and so it does make you more prone to heat stroke," ABC News crime analyst Brad Garrett said last year.

"Glow" party-goers are using the party's signature glow sticks to get more from the drug, officials say.

"The glow sticks that they use, the neon colors, enhance the effects of the drug Molly," said Andrew Carey, the acting prosecutor for Middlesex County, N.J.

Law enforcement agencies in New Jersey told ABC News they are now increasing their monitoring of "glow" parties and similar events after several attendees needed hospitalization after using Molly.

Officials say they have increased the police presence outside of clubs where the parties are taking place and are doing outreach to educate parents.

Party promoters, some of whom, officials say, have hired their own private ambulances in order to avoid calling 911, tell ABC News they are creating a safe environment for teens and don't condone illegal drug use.

"We have a countless number of procedures put in place to ensure a secure environment for our customers and peace of mind for parents," HyperGlow Tour LLC, which bills itself as "America's largest touring EDM glow party," said in a statement to ABC News.