The latest episode of The Mandalorian introduced an Imperial torture device called a mind flayer. Not a creature but still …
Turns out it was not the first time the Mind Flayer device was mentioned. It was mentioned by Kara Dune in Chapter 8: Redemption.
Then there is the tentacled, brain-bending, Mairan. One named Bor Gullet appeared in the film Rogue One. Another showed up in the comic Doctor Aphra #21.
In the former, we have use of the name for a brain-destroying machine, and in the latter a brain-bending tentacled creature.
This is 100% speculative fan fiction of how I imagine part of this going down:
Kara Dune in Chapter 8: Redemption mentions a "Mind Flayer" on December 27, 2019, it could be the Mairan depiction started it, or a combination.
D&D Franchise Team: Hey, we own that name, you know Stranger Things pays us to use it, you need to work with us to use that. (People keep maintaining Stranger Things licensed it, though there is zero press or statements from either party to back that up, but for this, I'll go with it).
Disney Legal (internally): Checks trademark registry.
Disney Legal to Wotc: "No."
D&D Franchise Team (internally): They are taking our IP! We need to stop this kind of thing.
WotC Licensing Team (internally): Hello no they don't! See, we keep telling you all this OGL stuff is wack. Open Source is so last decade, even in software when it comes to corporations.
I then picture the WotC Licensing Team and Disney Legal doing a dance of WotC saying "well how about this contract or license," and Disney replying "nope," every time.
All of this stocked part of the OGL debacle, making Kyle Brink's mention of the fear of large corporations stealing D&D IP factual, though still weird to connect to the OGL.
I also see the Star Wars creative getting wind of all of this at some corporate confab and going, "oh, that bothers them, they do know this is Star Wars, we love D&D and there is nothing more Star Wars than making call outs like this, so...let's do it again!"
One more time, this is just what I imagine in my head.