What other explanation can there be for Meet Dave, in which Murphy plays an extraterrestrial vessel captained by – who else? – Eddie Murphy. Producers have long sought to maximize the former SNL star’s drawing power by casting him in multiple roles, a tactic that paid off handsomely in Coming to America and last year’s Norbit. Here, Murphy once again embraces dual leads, to no great effect.

He plays Dave, the tiny leader of a tribe of thimble-sized aliens whose planet will expire without a generous helping of earth’s water supply. With a mostly loyal crew (the notable exception being The Office’s Ed Helms) and a spaceship built to resemble a larger version of himself, Dave arrives at Liberty Island with plans to drain the Atlantic before returning home. Problem is, he develops a soft spot for mankind, even as his mechanical human-sized alter ego marches stiffly through the streets, clumsily acclimating himself to (and sometimes terrorizing) modern-day Manhattan.

Meet Dave was co-written by Bill Corbett, whose Mystery Science Theater 3000 scraped and amiably skewered the bottom of the sci-fi barrel, long-forgotten schlock-fests like Radar Men From the Moon and Attack of the Giant Leeches. His latest is a step above those movies – it’s at least competent, even while riddled with plot holes large enough for Dave and all his diminutive comrades to tumble through – but in this case, only one question need be asked: Is it funny?

Not often enough. Murphy is capable of making mediocre material seem fresh, especially when he commits his still-boundless energy to a character, but he shows only a passing interest in Dave, and it’s hard to blame him. Besides a grotesquely exaggerated smile that recalls Cesar Romero’s Joker and a hopelessly awkward approach to conversation – “My colon is impacted,” his robotic other proudly declares after winning a hot dog-eating competition – Dave lacks any hint of the charisma that helped make Murphy a legitimate A-list talent.

When Dave’s fish-out-of-water mishaps fall flat, Corbett and co-author Rob Greenberg (TV’s Frasier) fill in the considerable downtime with lazy one-liners (“There’s been a gas leak… it’s silent, but not deadly!”) and racial and sexual stereotypes. It’s enough to drive even the most patient moviegoer to distraction; I used the time to count the commercial entities gratuitously plugged in the film. Among them: Old Navy, Macintosh, McDonalds and Eddie Murphy.