Black Spot on Bazooka Joe?

[SteezySPS]

I always dip and take macros of new incoming corals for record and pests. I took in my friends chalice today and found this mysterious black spot. It doesnt look dead, just looks like an ink blot. could it be caused by the luogol's iodide or coral rx pro I used for dipping?
Thanks in advance.

 

[revhtree Verified Admin]

That's weird!

 

[redwine1234]

my chalice was like that 1month ago, and the black spot peeled off bt itself. After the tissue is renewed take good care of it and it'd be back to normal.