Unknown live oak; what is this pest?

[BonsaiManic]

I dug this up about 3 years ago, and I haven't done anything with it so far. This morning I noticed dozens of tan, fuzzy lumps on the undersides of the leaves. It is the only oak I have, and no other trees are affected...
...so far. As it is so late in the season, I don't want to defoliate, as it's never seemed especially strong. Is this some sort of insect larva! A fungus? Google keeps telling me they are almonds, which would be cool, considering how I've never grafted anything at at all in my life.

Since it's a free tree, and just surviving, it won't hurt me too much to lose it, but it seems like it might be good practice material. Any help or advice would be appreciated. Thank you.

 

[vesper818]

Looks like the Wooly Mammoth Aphid...

 

[BrianBay9]

Oak flake gall maybe? https://bygl.osu.edu/node/2035

 

[Orion_metalhead]

Definitely not almonds. Lol

 

[BonsaiManic]

Oak flake gall maybe? https://bygl.osu.edu/node/2035

You got me on the right track. Turns out to be woolly oak gall. I'm not very familiar with Quercus, and, well, sometimes my researching capabilities are sub-par. Thanks for your input!
From what I just read, I can leave it alone, and next year I may not have a problem at all.

 

[BonsaiManic]

Definitely not almonds. Lol

Why not? All the Bnuts here hang from the undersides of leaves...
...or am I the only one?

 

[Srt8madness]

You got me on the right track. Turns out to be woolly oak gall. I'm not very familiar with Quercus, and, well, sometimes my researching capabilities are sub-par. Thanks for your input!
From what I just read, I can leave it alone, and next year I may not have a problem at all.

I've seen those on water oaks my whole life. I used to think it was egg sacs but I believe gall is the right area of focus