Have this plate coral about 3 months always looked good. Today it looks like the pic. Is it trying to sting other coral ? What is the web coming out of it ?
Yes, it is reaching out to digest the neighbors. When I have corals doing this, I move the active reacher so that it can't reach and injure anything downstream.
Looks to be either mesenterial filaments or just shedding mucus. I haven't seen any Fungiid extend mesenterial filaments before. Usually, when a coral shows mesenterial filaments anywhere other than the mouth, it means the coral is damaged. Aggressive corals usually extend their mesenterial filaments from their mouth.