Hi Matt. This isn't a flower at all, but a new plant. This sometimes happens in some species, usually if the
apex is damaged or if the plant has some other kind of damage, like from spider mites. The red color is generally temporary until the new plant gets some sun (it also happens if the plant is in too much sun). A wide angle shot of your plant would tell the genus, maybe even the species. It looks like a Notocactus of some sort.