Hi Sarah, I'm so sorry you're going through this with Hulk. (Love his name by the way), it's really scary when they swallow things they're not supposed to, and as careful as we are it happens, they are so quick. I have had this happen to me 3 times with my male Bulldozer, he is my sweat sock eater. He always seems to find socks, especially my little grandsons', and he swallows them before I can get them away from him. He has always been able to pass them either by throwing them up, or pooping them out. It can take up to a week, and once he passed it a month later. The whole time he was acting normal, eating drinking, playing. Then one day he would just throw up a sock, or poop it out. Only once did he show any signs of being sick from it, he started with diarrhea, then he vomited, even water would come back up, he was drooling water from his mouth, and he was lethargic. These are all signs of an obstruction, and are what you want to look for. I took Dozer to the vet, and she gave him IV fluids, pain medication, a laxative, and sent me home with some prescription Science Diet high fibre dog food to help him move his bowels. Later that evening he was able to poop out the sock, and we avoided having to do surgery. Hulk will probably end up,vomiting up or pooping out the piece of Kong, you mentioned it was the size of a nickel, so it's not very big, and it's a rubber and smooth object, so nothing sharp that can puncture or hurt him inside. It may irritate his tummy and cause the diarrhea or vomiting before he passes it, and it may take a few days, but should pass easily. Keep an eye on him, and check his poop to see if it passes, but take him to the vet if he shows signs of illness, or obstruction. I hope he feels better soon, and he is able to pass the piece of toy. Please keep us posted on how Hulk is doing.