What is this thing? Is it harmful?

[saltwater1]

So I once had Frogspawn on the same rock but it somehow died… thought maybe it was because i introduced it to my tank quickly. But before it died this thing started growing from the side. At first I thought it was a Kenya tree but now I’m wondering if this is harmful.

 

[JGT]

Appears to be some type of soft coral.

 

[NoohpyT]

looks like a kenya tree