Weird mass with leaf shape

[angelos reef]

What up guys first post here bought this Goni a week ago noticed a small mass I thought to be a baby rock flower nem at the time it was only about a half a mm very hard to see but now it’s gotta a bit larger probably almost 3 -5 mm it’s stationary and doesn’t effect the coral this pic was at lights on and it still extends fully through the day wondering if anyone’s seen it and knows what it is looked around and didn’t have any luck

 

[bradleym]

Offhand I'm going to say colonial tunicates.