A film like “Lamb,” with such a strange plot, at least on paper, needs to be very aware of the trappings that might come with relying too much on its central gimmick. The fact that it somewhat does is a testament to its rookie writer-director. This slight and inconsequential film has childless couple Maria (Noomi Rapace) and Ingvar (Hilmir Snær Gudnason), living a mundane existence in rural Iceland, making an alarming discovery in their sheep barn: a baby with the face of a lamb appears out of nowhere, part of the herd, with no explanation given whatsoever. “Lamb” is supposed to be some kind of metaphorical treatise on the anxieties of parenting — having suffered tragedy, our central couple feels invigorated, bottle-feeding the lamb baby, and cuddling her to sleep. It all has to do with Maria and Ingvar’s longing for the parenting experience, get it? The all-too-obvious metaphors get shaken up a little when Ingvar’s grotesque brother Pétur (Björn Hlynur Haraldsson) turns up broke and bewildered, wondering “What the fuck is this?” Both eerie and deadpan, Valdimar Jóhannsson's atmospheric folk-horror-dramedy, although incredibly silly, eventually turns dark, and although stifling at times, represents an unlikely original statement. [B-]