** (2 stars out of 5)
Are they Ux-mal? Calamarain? Free-roaming full-torso vaporous apparitions? They claim to be from subspace but they're not making any friends or asking for volunteers. They just want you for your bodies!
Once more retreating to the Catwalk seems like the thing to do. Why have built it, otherwise? And Phlox turns out to be immune, so he can set up the mechanical traps. If he knew anything about mechanisms. And as long as he doesn't cross the streams.
The bodiless creatures find the right host to hit on women awkwardly like some total creepy spazchow: Malcolm Reed, everybody! He gloms onto a lady in the turbolift, and accosts T'Pol in her under-roos.
I finally figured out who they are: Ghoulies. They'll get you in the end.
"The Crossing" is slightly superior to "The Lights of Zetar" and worse than "Power Play" on the Ghost Trope spectrum. Not even a token effort to help the ghosts? O.K., so they're probably all bad, but today it's just hook 'em, book 'em, cook 'em. Snore, bore, tomorrow there's more.