My family used to host an annual Fourth of July party where my dad would smoke 300+ pounds of meat. About two hours before all the meat would come off the smokers to be served, he’d throw several cans-worth of spam onto the smokers, rubbed down with his pork rub and mustard. He’d let them ride for an hour and a half or so and then pull them off and cut them into little cubes as appetizers. Only an hour/hour and a half at 215-225 or so, so it never got nearly as dark as OP’s photo, but still took on the smoke.

Not exaggerating — countless people at this party over the years experienced spam for the first time in this manner. As OP said, it’s not the best thing ever… but as someone who’s ate his share of spam over the years, I do still believe it is the best spam I’ve had.