"Ohh, that guy!" Heiji's expression eased somewhat. "Nah, I ain't talkin' about him. I mean, he's got a bit of that aura thing goin' on, but it's not as..."

Cue Heiji trying to express creepiness with his hands. It mostly involved moving his fingers around like claws and wiggling them around. Someone might use similar gestures to describe an octopus. Or a facehugger.