Like a comet in an irregular orbit, It Came From Beyond has returned to menace Manhattan, bearing down on Off-Broadway while emanating just enough charm and good will to keep from crashing. This sci-fi musical was spawned in 2005 at the New York Musical Festival, then rose again the next year in Los Angeles. Now, back for an oddball run of Tuesday-only performances, it turns out that, despite the threatening title, it has come in peace. And that’s the problem. Meant as an homage to the 1950s and as a parody of that era’s Cold War monster flicks (most obviously, It Came From Outer Space), playwright Cornell Christianson’s script is campy, but not sufficiently outrageous; other-worldly, but not scary. And opportunities to freshen the writing to reflect current political and societal upheaval have gone untaken.