What is growing on my stopper?

[Brif]

I have a 1/2 gal jug that I cultured a brett/lacto blend in. (TYB Amalg II and LActo Blend). It was a hoppy low gravity wort, the blend got going, fermented, and grew a thin pellicle. I pitched the blend 3 months ago, and I've been meaning to feed it, but I haven't touched it. Pretty sure this is a new growth in last few days. pic attached.

Any ideas?
It doesn't look hairy or fuzzy or chalky to me. almost looks crystalline in structure, but its not shiny.

 

[RPh_Guy]

Probably just the culture trying to escape along the seams of the airlock

 

[GilaMinumBeer]

Aliens. It's Aliens.

 

[Brif]

hmm, aliens I am fine with. Wondering though if anyone has had a run in with these guys before.
I'm hoping they don't have an affinity for messing things up as this culture will go into other beers.
Anyone seen this or something similar before?

 

[RPh_Guy]

What's the worst thing that could happen?

 

[Brif]

I suppose the worst thing would be that this is evidence of something other than brett & lacto in this culture, something detrimental that I then pitch into one (or several) of my small batch aging beers resulting in something unusable. I'm certainly not expecting that to happen, but I've never seen this before in any of my other long-term aging beers, so curious if others see it regularly. Rather than ignore it thought I'd toss it out there

 

[ong]

When I’ve let PBW dry on something, it has that kind of crystalline structure. Maybe something dripped on the stopper?