I believe you're right. It looks like a type of fungus. Fungus is interesting stuff. It grows in cracks in driftwood where food falls and is neither a plant nor an animal. It will go away once it uses up the food. If you're a little liberal with your feeding, the fungus will hang around for some time.
The only thing I know that will get rid of it are Ramshorn snails. Those little guys love it. These snails are good for your tank, I have them in all my planted tanks. They'll clean up all dead leaves and fish material, but won't damage healthy plants. They'll grow to the size of a dime and come in different colors.
"Fear not, my young apprentice. Just change the tank water."