Which is the spiciest chilli in the world?

In October 2023 Guinness World Records named Pepper X the hottest chilli pepper in the world, with an average rating of about 2.69 million Scoville Heat Units. It was bred by Ed Currie of the PuckerButt Pepper Company in South Carolina, the same grower who created the Carolina Reaper, which held the title from 2013 with an average of about 1.64 million units. For comparison, a jalapeño usually rates between about 2,500 and 8,000 units. The Scoville scale was devised by the American pharmacist Wilbur Scoville in 1912 and measures the concentration of capsaicin, the chemical that makes chillies burn. Pure capsaicin rates around 16 million units.