Platypus

From Shadow Unit Wiki

Platypus is a nickname for Chaz Villette. It presumably comes from the fact that a single platypus can eat two pounds of food each day (or half its body weight [1]), and refers to Chaz's beta-fueled appetite.

Chronologically, the first reference to Chaz as "Platypus" comes from episode 1x02, "Knock on Coffins":

Fortunately, so far the field team had been getting by on old fashioned street-pounding, but Chaz had been quietly terrified that the call would come in for some heavy database herding and he'd be the only one available to do it. So when somebody said from the doorway, "Hey, Platypus, get out of my chair," he almost crowed with joy.

Instead, he blanked and locked the screens--reflexively: Falkner was a bit of a martinet about it and Hafs was worse--rose awkwardly and said, "Hey! It's Eliot Ness! There's still six doughnuts in the kitchen." [2]

Platypus is also part of the tagline for the WTF Network.