A 62-year-old man came to a dentist to have his tooth 44 extracted. During examination he suddenly fell unconscious. His breathing and pulse are slow, his head is bowed, his arms are flexed in the elbows and wrists, his legs are stretched out, and his jaws are clenched tight. The patient developed clonic convulsion and started foaming at the mouth. His pupils are dilated and unresponsive to light. 1.5 minutes later, the patient's muscles relaxed. The patient is mentally confused. What is the most likely diagnosis in this case?