Is this hazardous to my health!?? WHat is it?!! Is it mold???

Its mushrooms growing from the bacteria in the wall from a leak. They are hazardous only if you eat them. Wear some rubber gloves and cut them out of the wall as best you can. Fill the crack with silicone caulk. Check to see if the drywall is Water Rock. Replace it if not. Caulk good around all cracks to keep them from growing elsewhere.