What is this?

Pollen sack aka bananas. Agree with fan off, wet tweezers or just pinch it off with fingers if your dont have sausage fingers. lols. There will be more elsewhere so go hunting ever day and rip em off the second u see em. It happens and even if some buds get seeds in em, once the bud is proper dry, u can just roll a bud between your fingers loosely and most of the seeds fall out. I had a lemon haze self seed and had half a pound of seedy bud, was still good thou. A pain to pick seeds out but hey thats how they did it in the big outdoor fields in africa and india back in the day. Seeds in bud isnt the end of the world ok. A pain in the ass, but you still get plenty of smoke out of it.