Serotonin Syndrome: This condition is caused by an excess of serotonin in the body, which can occur when multiple serotonergic substances are taken together, such as Prozac (an SSRI) and certain psychedelics like magic mushrooms. Symptoms include confusion, agitation, headache, changes in blood pressure, rapid heart rate, dilation of pupils, loss of muscle coordination or twitching muscles, and heavy sweating, many of which are present in this patient.

Cannabinoid Hyperemesis Syndrome: Given the high dose of THC, this condition is a possibility, characterized by recurrent episodes of severe vomiting, often accompanied by abdominal pain and weight loss, but the presence of nausea and the other symptoms could align with this diagnosis.
Psychedelic-induced Psychosis: The use of magic mushrooms and high-THC marijuana can induce psychotic episodes, including delusions and erratic behavior, which are observed in this patient.
Adverse Reaction to Polypharmacy: The combination of prescribed medication (Prozac) with recreational substances (magic mushrooms and high-THC marijuana) increases the risk of adverse reactions, which could explain the wide range of symptoms presented.

Neuroleptic Malignant Syndrome (NMS): Although less likely given the specific substances involved, NMS is a life-threatening neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic medication. It can present with fever, confusion, rigid muscles, variable blood pressure, and autonomic dysfunction, making it crucial not to miss.
Status Epilepticus: The muscle spasms and altered mental status could potentially indicate seizures, especially if the patient has a history of seizure disorders or if the substances taken are known to lower the seizure threshold.
Acute Coronary Syndrome or Cardiac Arrhythmias: The increased blood pressure and heart rate, combined with the potential for substances to affect cardiac function, necessitate consideration of cardiac causes.

Anticholinergic Toxicity: Although the substances mentioned do not typically cause anticholinergic toxicity, the presence of delirium, confusion, and altered mental status, along with autonomic instability, could suggest this diagnosis if other causes are ruled out.
Withdrawal from Other Substances: If the patient has a history of using other substances regularly, withdrawal could be considered, especially if the timeline of substance use and cessation aligns with the onset of symptoms.