Wow! I'm super intrigued! I was scraping this stuff off at first! I'll try to get some better pictures and post them.
Answering some previous questions ...
How long has the hardscape been in the water? - driftwood has been in there a long time (got it in 2014) and other items have been in there a long time as well
Did you treat/scrub/disinfect the driftwood? - I rinsed and soaked it only, but that was a long time ago
Purchase wood/remove from local waterway? - no, it was an online order
Feed live foods? - no
Seeing windows out the other side of tank? - sorry, no ๐ just reflection of windows behind me
What does it feel like? - soft, squishy, slippery? I should take some out and let it dry
Grows/continues to get bigger? - it appears to get longer at least, maybe not thicker/bigger
Break some off, will it reattach to a different surface? - don't know, good idea for an experiment! It appears to just start growing in different locations.
Test water basics? - they are good, I can post numbers, you can see white crushed coral because I needed to get the pH up to make the snails happier ๐ and to counteract the driftwood
Thank you for the complements on the plecos! The black pleco is healthy ... or at least he creates enough poop to make me think he is! ๐