What am I?

[h8edpurdie]

My sister went and bought some live rock for her tank and ended up with a hitchhiker. She sent me these photos asking about the white thing. I'm not sure what it is. Any help is appreciated.

BTW I've already addressed her on the cyano lol.

 

[Crabs McJones]

#reefsquad I've never seen anything like this

 

[DLHDesign]

Alien lifeform?

Nope; never seen it either. Following along to find out...

 

[cmcoker]

Someone posted something similar recently, think it was whelk eggs [emoji46]
Here's that thread https://www.reef2reef.com/index.php?threads/361730/

 

[Scotty Buttons]

Wow. I just googled marine whelks... those are some crazy looking creatures. Wouldn't want one of those in my tank

 

[KJ]

Whelk eggs!

 

[jsker]

This is a odd one.

 

[Kamden Uelton]

I want to say Tunicate but idk...

 

[h8edpurdie]

Thank you, everyone, for your input. I've Googled whelk eggs and this looks pretty spot on. I've passed the info over to my sister so hopefully she takes quick action in getting them removed, as well as looking for anything else.