Creature from Alan Dean Foster's Splinter of the Mind's Eye. Visually designed for the Dark Horse Comics adaptation by Chris Sprouse. Planned for it to appear in this Edge of the Empire session, but my son's PC went in another direction thus never encountered the beast.
Eeeeeeeeeeeeeeeeeeeeeeeeeeeee, run away, run away!!
There's never a bad time to have a giant albino worm pop out of the sewers to attack the player characters.
I hear you on that, if you're the Game Master.