Originally Posted by earwig
That looks like white film mold. You may not have sanitized good enough. That typically doesn't cause a flavor defect so you can go ahead and bottle (syphon from beneath it into the bottling bucket). It will show up again in the bottles but again, it shouldn't change the taste much if at all.
I agree that it is an infection of some kind. I don't have enough experience with all the different types to know if it is mold or not, but this looks similar to some of the pellicles I have seen on the beers I've made when intentionally adding the dregs of sour beers. If it is a lactobacillus, pediococcus, or Brettanomyces infection, there will definitely be a flavor effect. Not necessarily ruined if you like that sort of thing, but definitely might turn out funky and/or sour.