Biting into the “hottest pepper in the world” sounds painful enough. But for one man, the daring feat resulted in excruciating headaches, known as “thunderclap” headaches, according to a new report of his case.

The 34-year-old man ate the pepper, a Carolina Reaper, as a part of a hot-pepper-eating contest. This particular pepper is considered the hottest chili pepper in the world, according to the report, published today (April 9) in the journal BMJ Case Reports. (The Carolina Reaper has a “heat” of about 1.5 million Scoville units, according to Guinness World Records; for comparison, a jalapeño comes in at around 5,000.)

Immediately after eating the pepper, the man experienced dry heaves; he then developed intense pain in his neck and back of his head. Over the next few days, he went through several episodes of brief but excruciating headaches. These types of headaches are known as thunderclap headaches; they strike suddenly and peak within 60 seconds, according to the Mayo Clinic. [Ouch: 10 Odd Causes of Headaches]

The headaches were so painful that the man went to the emergency room. Doctors performed several tests for neurological conditions, which came back negative.