We have grown a Starfish flower (Stapelia gigantea) for a number of years. It typically takes about an hour for the blossom to fully open. The open blossom measures about 5 inches across. While it is covered in hairs, there are no spines. I took a time lapse series of photos with my GoPro camera today and converted it into a short video.
The flower was already starting to open when I began the time lapse photos. One more chance this year to capture the entire sequence (one blossom has not yet opened). I hope you enjoy. Yes, I had to add some music reminiscent of the 60s. This track is from Soundzabound and can be used on the web per my license.
This is what the fully open blossom looks like.