Green growth not bubble algae...


Reefing newb
I'm not exactly sure what this is. I've been searching the internet for some ideas but still don't have the slightest clue. So I joined this site in hopes for solving this mystery. It's just a green "bubblish" growth in 2 patches. We tried scrubbing it with a tooth brush to see if that would do anything and it didn't budge like bubble algae would. Also it looks nothing like it. We've identified everything else (we've seen so far) except for this little number.
No it's not green bubble algae. We've had a run in with that because the person we got our live rocks from had it. this is growing completely differently. If I'm able to get a decent picture I'll certainly try.
Is it possible that it's just a round bulbous part of the rock that's just green? Can you touch it with your finger and feel the texture? Is it slimy, or rough?
Woke up this morning and one of the spots with the growth is completely gone. along with the rock being quite clean in that area. I'm thinking it could have been the peppermint shrimp.
Ok I think from all the help I've decided it is a type of Caulerpa macroalgae. I'm supposing not all Caulerpa growth grow in strands like the pics I've been seeing. It just makes the most probable sense. Thanks for all the help you guys! And I used to have an emerald crab. poor little fella didn't make it through the night without the niger trigger getting to it :( luckily the peppermint shrimp is good at hiding.