It's a giant tube, sent down by aliens, to suck people up into their space ships! (Startrek stole the beaming up thing, so they didn't want to infringe on copyrights.)
See? See? It's sucking Myst up, by her hair, and that's why she's got her hand near her mouth going "Oh, my goodness. Whatever shall I do?" And it's stolen all her clothes, first. Sucked them off, y'know? So, now she's cold, hench the OBVIOUS T.H.O.
*pauses for breath* Hmm... did I read too much into that?