The nickname came from playing NHL94 with my buddy online. We occasionally play the game where we start on opposite ends of the alphabet and work through the teams, one team at a time, until you lose a game. For example, let's say I start with the Anaheim Mighty Ducks and he starts with the Winnipeg Jets. He wins game one. So in game two, I would be the Boston Bruins while he would remain the Winnipeg Jets. If I won that game, I would remain the Boston Bruins and he would become the Washington Capitals. Thus it goes until we get bored and move to something else.
Eventually I got stuck on the Montreal Canadiens. I kept winning despite not being a big fan of them. In the game, they have a center named Kirk Muller whose name shows up as K Muller, which we then started pronouncing as one word: "Kmuller" - and after a bunch of goals by Kmuller, he became "Kmuller the Cruller," which then became a stupid chant/slogan of "Kmuller the Cruller, half man, half donut."
So there you go. It's all Kirk Muller and NHL94's fault.