When Justin Schmidt started studying insects four decades ago, the University of Arizona entomologist was originally only interested in the social lives of ants, wasps and bees. Along the way, he saw scientific value in measuring the pain they inflict. The result? His Pain Scale for Stinging Insects, which has captured public imagination more than the average scholarly bug study—and helped inspire HISTORY’s new show “Kings of Pain.” Below, a sampling of entries from Schmidt’s pain index:

Like any intrepid bug researcher, Schmidt suffered his share of accidental stings while observing his subjects and collecting samples. But after realizing the value in measuring the pain of those stings, he started actively seeking to induce the creatures’ defensive reaction by placing them on his arm and gently pressing down until they felt threatened enough to plunge their stinger into his flesh. The results are detailed in his pain scale, featured in his 2016 book The Sting of the Wild: The Story of the Man Who Got Stung for Science.

Schmidt’s index, which measures the hurt of 83 different insects on a scale from one to four—and includes poetic descriptions of each sting—is one of the inspirations behind the new HISTORY show “Kings of Pain.” In it, wildlife biologist Adam Thorn and researcher Rob “Caveman” Alleva travel the world to compile their own pain scale, one that goes beyond bugs to include the bites and stings of creatures like scorpions, lionfish, pythons and piranhas. Their hair-raising research also extends Schmidt’s work by rating the pain in more detail: its intensity, duration and damage, each on a scale from one to 10.

For his part, Schmidt says he is thrilled to see his research tested and pushed in new directions: “I'm glad you're brave enough to do it,” he recently told Thorn and Alleva. “And foolish enough.”

New episodes of "Kings of Pain premiere every Tuesday at 10/9c on HISTORY. Watch full episodes now.