I can't tell from your picture...too fuzzy, but google "acro crabs" and see if it's that. If acro crabs, no problem. If it's "hairy," than with caution.
Fuzzy crabs eat acro... So pull that out and dip the coral if u can while its dipped try and get him out fasted so that way the coral doesn't have to stay in the dip that long. The dip stresses corals out...