To that I would reply, "They're a variation on Uncle Ray pants!"
To which you'd answer, "Huh? Off your meds again, I see."
But of course I have an explanation, much longer than the subject warrants, I assure you. Uncle Ray pants are basically Grandpa Pants but because we didn't have a grandpa, we had to substitute Uncle Ray as the oldest rotund male relative in our family, see?

Now that we've cleared that up, what on earth is the salmon pants variation? I will tell you! Double Post's in-laws own a house in swanky Lake Geneva, Wisconsin, where Chicago's wealthy have always "summered." We were sitting on a bench near "the club" (the same club where Dilf learned his patented "leg guitar to AC/DC's Shook Me All Night Long" dance move, but that's another story) when we saw a man walk by. We were playing one of our people-watching games, where we judge passers-by by whether or not they look like we'd face a dire emergency with them -- like, end of the world kinda stuff. Anyways. Double Post saw this guy walk by and she said, "No way am I getting stuck with Salmon Pants!"
See, he was wearing salmon-colored golf pants, with a white braided leather belt anchoring them up midway between his navel and his clavicle. He was probably in his late 40's, nowhere NEAR old enough to be wearing Uncle Ray pants. Thus, the Salmon Pants variation was born. Now we use it all the time. "Do these look like Salmon Pants?" "I don't care if these are Salmon Pants; they're comfortable." "Take those off! They're Salmon Pants!"
I had a hard time finding a suitable example of Salmon Pants to illustrate my point; apparently most people don't like to be photographed in their Salmon Pants. However, the sadistic bastards have no problem abusing their children thusly:

For shame, parents. For shame.