Looks like scale. I read somewhere that you could take a q-tip dip it in alcohol and dab it on it and it should be able to be removed. Or you could try some neem oil.

How about a picture of the whole palm so that we can get an idea of the size, form, etc. Your image doesn't help much, but I am assuming that those dark spots are what you are referring to as bug/mushroom. Right? Could be scale insects, I agree.

If so, you'll probably need to take a soft cloth and some very diluted soap and water and wipe each frond until clean. Then, occasional mists of alcohol and water or horticultural oil may help keep them under control.

Scale insects are very difficult to get rid of on palms, which is why I'd like to see a picture of the whole plant. We'll also be able to determine if it is even worth saving. When an infestation gets too advanced, the best thing to do is get rid of the whole plant. Kick it to the curb!