I actually made this for my son's 8th birthday, about - oh, 8 months ago. It's a "better than whatever" cake (this is a family friendly site!). The grass is cool whip so it didn't hold it's shape as much as I wanted. The zombie heads and plants are all cake balls as those are my kids favorite for b-days. Do you see the horrendous sunflowers in the back? I used old candy melts. Whoops! Won't make that mistake again. It went on like crusty frosting instead of drizzling chocolate. (Learn from my mistakes here peeps!)
The awesome thing about doing zombie heads is that you can make it hideous and it looks even better...no talent required! Another point of interest is the edible markers I used. I got the Wilton brand from Michaels (the smaller point). I WOULD NOT purchase these again. It took me forever to get it to show up on the candy coating and it only worked for a few until the pen wouldn't work at all anymore. I think I'll stick to melted chocolate in a candy melt bottle (I'll show you on another post!). Much better and much more consistent results there.
BTW, is Plants vs. Zombies still in vogue?