“The Watch” is a wretchedly unfunny comedy and a new low for its star, Ben Stiller.

On paper, and in the advertising campaign, “The Watch” is about Stiller forming a run of the mill neighborhood watch with Vince Vaughn, Jonah Hill and British import Richard Ayoade, and they somehow wind up fighting aliens.

In execution, the movie barely cares about this premise and would rather join the ranks of relentlessly vulgar comedies. Upon founding the group, Stiller learns his recruits are a trio of immature nitwits who would rather drink beer and talk trash in Vaughn’s man cave than go on patrol. “Man cave” is one of those pop phrases I swore I would never use, but given this movie’s Neanderthal level of humor, it’s the only phrase that fits.