Answer:
Hallucinogens.
Step-by-step explanation:
STP, MDMA, and PCP fall into the category of Hallucinogens drugs because these drugs causes Hallucination. Due to these drugs the person observe and see things which are not present in real life. These drugs take the user to the world of imaginations and away from the reality. Hallucinogens drugs alter or change the perception, thoughts, and feelings of the person who is using it.