Thijs, you're very observant and I think you're right that the plant is a Ferocactus. It does appear the name on the tag was seemingly crossed out by somebody, and the radial spines are informative. For what it's worth, I would not be comfortable identifying the plant without seeing some younger spines near the growth point. I see no compelling reason to move it at this time.
F. chrysacanthus is supposed to get relatively big (over 3 feet tall and 1 foot wide) though I have never seen a plant anywhere near that size. It may also make 6-12 radial spines which tend to be insubstantial but in some cases may be "needle-like" according to my cactus book by Anderson. So those things check out.
Interestingly the location is given as 98108, which is a postal code near Seattle, Washington... maybe it's in a greenhouse there? The member who posted the photo has not posted anything for a year or so, but hopefully will check in at some time to help sort this mystery out.
