Coral base detachment???

[spawn]

Is there a known plant or anemone, that can grow underneath the base of a coral that causes the coral base to appear as though it is lifting from the rock surface? I have this on part of 1 acro base. The plant looks like a purple pot leaf about 1/8" in diameter & it retracts at dawn & dusk when the full lighting is is not on. The coral is in great health, lot's of new growth with excellent p.e. even right beside these things but it looks as though the coral is lifting off the rock because of them to the point it looks as though it could fall off.
Any idea's on what this may be & if they are bad?