What are the dangers of synthetic drugs?

Synthetic drugs have become popular due to the fact that people believe it'll give you a "safe" high. In addition, they’re easy to get a hold of and they're technically legal. These drugs are manmade, and as a result the potency of the drug is in the hands of the manufacturer, which makes every dose different. These drugs could be laced with other drugs like fentanyl. Even a small amount of fentanyl could cause an overdose because that's how powerful it is. Drug tests don't pick up on synthetic drug which is another reason why they're popular among teenagers, since many teens look for a way to get high without getting caught. You can't tell if someone has taken anything and there's no familiar odour with synthetic drugs - some are odourless. The use of synthetic drugs can have many side effects that include: anxiety, aggressive behaviour, paranoia, seizures, loss of consciousness, nausea, vomiting, and even coma or death.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).