Seems to be some sort of fungus growing, this commonly happens when driftwood is added to a tank. It should dissipate in a while. In the meanwhile, neocaridina shrimp have picked at it when I had fungus.
I put my driftwood in an ice chest and filled it with boiling water. The piece I found was a lot thicker, so I boiled it repeatedly over about a month. It got rid of any yucky stuff and all the tannins.