A good advice from someone who plays with Mo'Creatures on Hard mode: Don't make an underground base! You'll regret it deeply when you hear the sound of "HHhhRrrrr..." Boom! Boom! Boom!
I'll let your imagination tell what might happen..
Also ALWAYS carry a golden sword with you!
Welcome to DFTB, Don't Feed the Beast! They will still kill you
PS. Dying near a goat is a bad idea...