I got two different coral hitchhikers on some uncured gulf live rock I bought. When i first got them, they were nothing but white skeleton, but after a week or so I started noticing they were coming back! Here is the first one shortly after I noticed.
And here is a picture of it today... maybe a month and a half later.
Here is the other one almost completely dead...
Here it is recovered a little bit...
And here it is today...
This rock was out of water, just covered in wet paper towel, for over 48 hours. Amazing what can survive!