They look like "sea monkeys dancing to the oldies," notes a wayward NASA astronaut. He's speaking about the amphibianesque creatures on Planet 51, which resembles a cartoon version of the Happy Days set, with bulbous cars, streamlined diners, and a dim-witted populace enamored of scary alien invasion movies.

An uninspired computer-animated feature that may satisfy undiscriminating pipsqueaks and nearly no one else, Planet 51 is a low-IQ E.T. in reverse, with the human visitor, a square-jawed American spaceman by the name of Charles "Chuck" Baker (the voice of Dwayne Johnson), befriended by a green-skinned, antenna-topped kid. When the Earthling's presence becomes known, the army, and the masses, go into a panic.

Notable for its rip-offs (generous souls can call them homages) of (and to) WALL-E, 2001: A Space Odyssey, Star Wars, The Day the Earth Stood Still, Alien, The Terminator, and Grease, this soulless exercise in kiddie entertainment also boasts the larynxes of Justin Long (as the teen hero, Lem), Jessica Biel (his next-door neighbor and crush-object, Neera), Gary Oldman (a pompous general), and John Cleese (a monocle-sporting professor).

Like humans convinced that the end is nigh, and that aliens - or Roland Emmerich - are about to wreak apocalyptic havoc, the Planet 51ers wander around in dread of an invasion of UFOs. So when the way-off-his-trajectory Capt. Baker lands, loud and pointless freakouts ensue. There are chases, there are shoot-outs, there are misunderstandings and missed opportunities for reconciliation.

There are opportunities aplenty, too, to use the rest room and concession stands.

Written by a Shrek contributor (Joe Stillman) and directed by Jorge Blanco working with his Madrid-based Ilion Animation Studios team, Planet 51 has a bright color palette and next to no distinguishing features. The weirdest design element is the "hair" on the creatures' heads: Between their antennae sprout thick green-yellow clumps that look like little bananas.

Planet 51, home of the plantain-heads.EndText