Need help to identify potential problems

[Samoll]

Hi. I'm new to the hobby and have been running my tank since December last year.
I have noticed a small white patch on the stem of my hammer coral and it seems to be getting bigger. Can't find any pictures that look similar on line so am at a loss. Any help would be appreciated.

 

[Drummingbaker2010]

Hi. I'm new to the hobby and have been running my tank since December last year.
I have noticed a small white patch on the stem of my hammer coral and it seems to be getting bigger. Can't find any pictures that look similar on line so am at a loss. Any help would be appreciated.

I have something similar looking on the back of my tank. it doesn't look that defined in the middle, but the edges look similar. Someone suggested it might be a type of flat worm, but I'm not sure.

 

[Samoll]

I was asked if it moved and when I nudged it it came off in one piece. The coral is fine underneath. But I did notice a few bug like things under it.

 

[Drummingbaker2010]

weird. I don't know what it is, but I don't think I would want it there. I would remove it.