Regulus of Hogwarts: Lord of the Stars

"I mean," Sirius said, disbelief threading through his voice as he pointed, "this is your pet? A spider?"

Regulus didn't answer. He held out his hand, palm up. Baruk crawled from the collar, down the shoulder, along the arm, and dropped into his palm before hopping onto the desk.

Then onward, to the edge nearest Sirius.

He stopped there, two forelegs resting on the lip, upper body rising slightly, chelicerae opening and closing. Click-click-click.

Hard to say if it was a threat or a greeting.

He paced back and forth a few times, eight amber eyes sizing Sirius up from head to toe. Then he glanced back at Regulus.

Regulus gave a slight nod.

Baruk turned to face Sirius again. The chelicerae worked twice more, and then a short, clipped syllable: "...Baruk."

Sirius sat bolt upright, the force of it sending his chair skidding backward.