+1 on freakish resilence. I had a huge colony covering almost half of a 75. I didn't mind, because it looked nice, but then it started growing up a rock with a coral I liked, so I decided to kill in on that rock to prevent issues. I scraped all the flesh I could get at with a razor, then soaked the rock in scalding hot tap water for about 2-3 minutes (keeping the main coral out of the water of course), and then took a brush to it for a little. It took a couple weeks, but the darn stuff started growing new polyps wherever there was flesh I hadn't been able to remove.
Then, one day, all of it died with no warning. Wierdness.