It's the oil separator. Practically useless as is. You should replace it with an aftermarket oil separator, like a Cusco or Greddy item etc...
If it's not there, no harm will be coming to the engine, you'll just be venting the crankcase gases elsewhere. You should rectify the situation ASAP though as, it could be venting more into the inlet pipe which, will be warming the intake charge and diluting your fuel !