And he is. Part of the charm of this re-imagined "Wilfred," now in its third iteration since originating as a stoner short film and then becoming an Australian series from Gann and Adam Zwar, comes from the guest stars that seemingly appear from nowhere. Every role filled is surprising, but at the same time they play true to the type that we associate with the famous faces played them. When Jenna's boyfriend Drew is introduced, he's played by Chris Klein as an over-competitive jerk who Ryan can't stand and who makes Wilfred bristle. Klein thrives in the role, as it's like the warped and legitimate version of what would happen to Oz from "American Pie" if he were all grown up and once again insensitive.
The key to a successful guest star appearance requires an approach that's part "Law and Order" and part basic cable stunt-casting. The beauty of the "Law and Order" cameos came from so many actors getting their start there and evolving through the various shows, whether it'd be Phillip Seymour Hoffman in a throwaway role or Rainn Wilson as a deranged momma's boy right before becoming Dwight Schrute on "The Office." As for the stunt-casting, traditionally it's done to heighten awareness of a series. But "Wilfred" rolls through its episodes so lazily that when Williams pops up during "Progress" as a bearded caricature of Patch Adams, it's more of a surprise that it's played off without so much as a "On a very special 'Wilfred'..."
The characters are fleshed out further than brief one-shot appearances. Dwight Yoakam's Bruce is particularly fascinating, since he's not only been affected by Wilfred, but can see him in his "man-in-dog-suit" role. He could possibly be another figment of Ryan's imagination, but the delight he takes in reprising the same character as his doctor from "Crank" is incredible.
Likewise, Jane Kaczmarek's Beth, who appears in the episode "Pride," builds on the audience's sense memory of her as the mother in "Malcolm in the Middle." Wilfred encourages Ryan to get it on with her, while he really is trying to bang her son's plush giraffe. These guest spots aren't just designed to be a flavor of the week in terms of casting, but they're building upon the mythology that "Wilfred" is generating -- instead of being just another show about smoking pot and giving up on the working week.
By this point, it wouldn't be surprising to see Nathan Fillion show up in a giant hammer outfit or Steve Carrell as himself trying to figure out where he is. Regardless, they'll be the perfect foil for Wood's mystified, wide-eyed embodiment of a man's mental breakdown, as well as his realization that Williams isn't that good of a shrink.