Drove through this campground back in June, but ultimately decided not to stay there because most of the sites were full and the few available were quite small and had very little privacy.
That said, other sites sat further back from the little dirt road that winds through the campground, are larger, and definitely looked like good options. I think it is really a bit of luck as to which are reserved and which aren't.
Standard simple campsite amenities: toilets, firepits, tables. There's a little creek that runs through the campsite, and then a pretty large rock spire overhead (hence the name).
The area is near Big Sky so you'll have ample hiking and other activities to get up to if that's your thing.
Note - the camp host really stressed being bear aware, as this is grizzly country and he said they definitely do come through the camp on occasion. So have your bear spray ready and know how to handle your food to keep yourself safe.
Would definitely stay here if I could get one of the nicer, more private sites.