I can find no basis for them anywhere on the internet. Anyway, it's sort of immersion breaking. Here I am crossing terrain trying to find rancors only to have this tired spoof show up everywhere. So if they were a joke from when creatures were implemented, wouldn't it be time to remove them from spawns already?
With the multitude of random species that exist on Yavin 4, from plants that eat you, to giant spiders, and bears and whatnot, it's pretty likely there's a SW insect/creature that feigns being a plant in order to catch prey.
In either case, there's some ludicrously silly number of creatures in the game, with more being added/worked on, so the spawn rates aren't too bad.
/me shrugs. I don't care either way, but I'm not too fussed with them still spawning, they're the only "horde" creature that spawns in giant numbers I think? Locust-style mentality.
Speaking of spawn rates, I've come across the ominous Berry Monster on several hunts. Despite their ferocious appearance, they die quite easily. If you ever come across a group/herd/pack/cropping/whatever take aim and shoot. You won't regret it!