Reaper tilted his head in something of an See? Told you way once McCree had turned around, still keeping his eyes on those things as he slowly made his way closer. Didn't trust them to just be shadows, knowing what he could do, other things he'd heard about another creature that could just suddenly appear-

"Something attached to you, probably created by emotions," Obviously and simply how things worked in this place. "Other than that, couldn't tell you."