Not sure what these are either

[dedecv3]

These came on some live rock I bought from a local reefer who was breaking down his tank. He wasn't sure what they were and I have no idea either.

 

[shrimpy brains]

Interesting! Not much help, but I'll give you a bump. Looks like some sort of leather???

 

[emusinky]

It looks like the cabbage leather that I bought from LFS. It's easy to keep.

 

[spanko]

Yup cabbage leather Sinularia dura.
From live aquaria;
QUICK STATS
Care Level: Easy
Temperament: Semi-aggressive
Lighting: Moderate to High
Waterflow: Medium to Strong
Placement: Top
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025
Color Form: Tan
Origin: Fiji, Indo-Pacific, Maldives
Family: Alcyoniidae

 

[dedecv3]

Thanks again for your help!!