A reunion of Nick Frost and Simon Pegg—stars of the beloved comedy hybrids “Shaun of the Dead,” “Hot Fuzz,” and “The World’s End”—should produce abundant joy, especially given the promising concept of Amazon’s “Truth Seekers” to once again blend humor with another genre. And yet this 8-episode comedy is a shocking misfire, a deadly dull affair that feels much longer than even its 4-hour total runtime and produces an unbelievably small number of actual laughs and thrills. It’s a show that pushes so hard into its supernatural genre that it almost actively avoids actual comedy, but there’s nothing there to replace it. It’s understandable and even admirable to play the supernatural elements of a show like this straight instead of winking at the camera—and the films Frost/Pegg made for Edgar Wright have a similar strength in that they take their genre structure as seriously as their comedy—but it leads to a shockingly boring show here. The truth is what Wright does in those films with Frost and Pegg is much harder than it looks. Imagine a dull episode of “Ghost Adventures” with a little more British deadpan wit.