Aiieee, mutant giant ants! Thatís pretty much the gist of this Atomic Age relic, in which the radiation from the first A-bomb test turns a New Mexico colony into supersized marauders that threaten first the locals, and later (gasp!) the world. Still, journeyman director Gordon Douglas deserves credit for some efficient camerawork and for keeping the tone surprisingly creepy (for 1954) in the first few reels as a local cop (James Whitmore) and an FBI agent (James Arness) try to figure out whoís killing area desert dwellers and spilling sugar everywhere in the process. Unlike most í50s creature features, when the creatures finally show up, all googly eyes, mechanical mandibles, and fake-fur-covered antennae a-go-go, it doesnít send things into an uncorrectable kitsch tailspin. In fact, Them! is so earnest in its pseudoscientific didacticism that it verges on boring. But hey, giant ants, plus the sight of Arness squeezing his mutant 6-foot-7 self into the frame with the normal Hollywood thespians; in the ant-fighting sequences, his Korean War-era Army steel pot helmet fits him like a shower cap. Now thatís unnatural.