A 22-year-old university student is brought to the Emergency Department by friends who report he became acutely agitated, paranoid, and started experiencing auditory hallucinations during a party where recreational drugs were suspected. He has no past psychiatric history. On examination, he is tachycardic (120 bpm), hypertensive (160/100 mmHg), pupils are dilated, and he appears hypervigilant and anxious. What is the most likely substance responsible for this presentation?