I think if I served this cake, I'd really want to make sure that I knew my guests. Ever since seeing the Halloween movieI've always shuddered when I see a knife like that! Guess you could make one though out of cardboard too for the squeamish like me!
Note the graveyard around the outside of the cake. You could adapt any graveyard cake to be a zombie themed cake - just add a zombie coming out of the ground, or make one of the graves open!