John Pyper-Ferguson and Mark Pellegrino

Hell hath no fury like a coyotl scorned.

Brothers & Sisters actor John Pyper-Ferguson will guest-star on "Bad Moon Rising," the third episode of Grimm's second season, TVGuide.com has learned exclusively. He'll play Hayden Walker, a man who is mourning his deceased sister and wants to exact justice from Jarold (Mark Pellegrino) for disgracing his family name. Only problem? Hayden has to take his family to Portland to track Jarold down.

Lost's Mark Pellegrino to guest on Grimm

As previously reported, Pellegrino's Jarold is an old high school buddy of police detective Hank (Russell Hornsby), whose daughter goes missing. Both Hayden and Jarold are the coyotl type of Wesen, coyote-like creatures that are mean, nasty bullies who have a strong pack mentality and don't take kindly to those who turn their back them.

Pyper-Ferguson played Joe Whedon on the first season of Brothers & Sisters. He's also appeared on Castle, Fringe and Caprica.

The second season of Grimm will debut Monday, Aug. 13 at 10/9c before moving back to its regular Friday timeslot on Friday, Sept. 21 at 9/8c.