It's an experimental---individual builder? Some ex-mil birds are experimental only but this doesn't look like that, so I'm sticking with the one-off homebuilder.
My first thought was a Yak, based on the prop, what I could see of the engine, and the vented cowl (looks vaguely like the Yak 52's cowl). Nope, not a Yak. Wasn't familiar with Murphy aircraft, but after reading Dave's answer above, I visited their site (of course, the pic shows it saying "Murphy Moose"....). Yep, turns out they have a model that utilizes the M14P, same mill as the Yak 52.... go figure. I particulary like the graphics here of Bullwinkle, Boris and Natasha, something I hope to do someday to a Yak 52 if I can ever manage to procure one.... ($dreaming$.....)