Giant creatures are great. Especially giant version of things that are normally pretty tiny. Most people have no real idea what insects or the multitudinous types of worms or other tiny critters actually look like if they were magnified. So blowing them up to gigantic proportions makes things that are not only intimidating, but also weird.
Commentary by memnarch (who has not seen the movie)
A space leech now? I guess the budget ran out on importing space wyrms. Or maybe the space wyrms can't handle just how green this new place is. Like, wow, this is really bright. Can we go back a couple jumps? That cave or planetoid with the spike things looked way cooler than this, and it was easier to see things there.
So.... what's the end point here? Since hyperspace seems to be having problems at the moment, do they simply keep jumping around and trying to pick off the TIE fighters until there's a familiar planet to hang out at? In which case, what then? Hope that there's a useful thing on the planet? Actually, that'd be a pretty reasonable action. With how coincidences seem to happen and play out, we'll somehow end up back on, like, Ahch-To and there'll be something there that can help. Maybe Rey finds that she's still got a connection to the slime pit mirror cave or the fish people can help somehow.
Transcript
[SFX]: vreeeeooooowww... {a PIE fighter pursues the Falcon and its mirror image}
Finn: The liquified space-time must be messing with reality.
R2-D2: We need to recombine with our mirror image! Bad things will happen if we don’t!
Chewbacca: Can I bring us on a collision course and time it so we jump to lightspeed at the instant of impact?
Poe: Awesome!
GM: If you make a Piloting roll with a -7 penalty.
Chewbacca: Here goes nothing.
GM: You time the jump to hyperspace...
[SFX]: Whoooosshh!!!
GM: ... and again drop out.
[SFX]: Shooowwp!
[SFX]: vreeeeooooowww... vreeeeooooowww... {PIE fighters are still in pursuit}
[SFX]: pow! pow! {the fighters shoot at the Falcon}
GM: There’s no reflected Falcon—
Chewbacca: Great!
GM: —but ahead is a giant space leech, its maw large enough to engulf you!
[SFX]: vreeeeooooowww...
[SFX]: pow! pow!
Chewbacca: Are you taking challenge ideas directly from Pete now?
GM: It’d be a shame to waste a resource as devious as his mind.