Heck, they could have reused the asteroid field footage from "Mudd's Women" and "The Doomsday Machine" so Sulu was under a false but believable impression, right?
Because giant space daggers are ridiculous, while giant space amoebas, giant space Bugle chips, and giant space Greco-Roman God hands are normal occurrences?
(Man, wouldn't it stink to be in the middle of dealing with one ridiculous crisis and have another ridiculous crisis break out in the middle of it? ``Aw, man, annoying space children and Vaal ripped the space-time continuum a new one?'')