Hi all does anybody know what this is?

[Willba200]

Thought it was a piece of live rock that had fallen off, but in the last two weeks it has turned purple with things growing off it.

 

[Ljfdfireboy]

Hard to tell any chance of getting a better close up maybe some more light?

 

[Ricksreef]

Think you were right at first thought.It does look like a piece of your rock,notice white area in the above rock,probably fell from there.The turning in color is the Coraline algae covering the piece and it looks like it has some caulerpa algae sprigs growing from it.