Not sure if beneficial

There's some kind of hyphae growing around one of my apple tree starts. I'm not sure what it is. It doesn't seem to be negatively affecting the plant though. Monitoring it for now. Ever seen anything like it?

No , but it's cool looking.
John S
PDX OR

I usually see that when my soul is too moist and there isn't enough air flow. I don't know that it's very harmful but it tends to signal unhealthy conditions

Solid advice Matu. The leaves started to turn brown and curl up after a day. I ended up removing my fungus friend, pruning the leaves, draining the excess water, and taking the greenhouse top off to let it dry out some. Hoping it sprouts more leaves in a few days. If so, I'll try the greenhouse thing again with more air holes.

Luckily, Apple tree B has been isolated and appears to be thriving.