With the explanation, Mal feigned being distraught, hand going to his chest and giving Theresa a sad look, though the hint of a grin at the edge of his mouth might give him away. "It's terrible. I have a phobia of names, you see, so I have to give people nicknames in order to be able to tell them apart." His head leaned back, expression going thoughtful as he considered Theresa. "Think I'll designate you Dewey until further notice," he said with a nod.