nightmare-inspired creature

[JeenLeen]

I had a creepy not-quite-nightmare last night, that inspired a not necessarily evil monster for a game. I'm going to describe it, then discuss ideas of stating it in a game, but I was wondering if folk had ideas about stating it in any system or wanted to share similar inspirations.

Dream: I'm on the porch, and there's a kinda-dirty middle-to-small dog. Dirty and unkempt stray, but looks friendly and approaches. I pet it while talking to someone (a strange homeless woman.)
I notice there's some twigs and stuff stuck in the dog's fur. I get some out of it. Then, I see there's a plant, like a stem a few inches long, growing out of the fur. It looks like there's so much dirt that it took root. I pull the plant out, and see the tendrils of its roots pull out across its back. The poor thing winches, but seems okay with it.
Then I see another clump of dirt with some grass. I pull at it, and several small worms start swarming out. Grossed out, I move back, pulling off the plant, and several small beetles or bugs start swarming out as well.

That's when I woke up.

Basically, it's an undead-like critter, or a plant monster, that appears normal, and as you interact with it more, you realize it's a monster. Either a corpse that's had plants growing in it and bugs living in it, or a plant-monster.
I could see in D&D it being undead or an undead plant with some Disguise Self or illusion power that is hard to detect, but the DC gets lower as you interact with it.

[hamishspence]

Sounds to me a lot like Yellow Musk Zombies, which are created by the Yellow Musk Creeper plant:

http://paizo.com/pathfinderRPG/prd/b...skCreeper.html

(I think in 3rd ed, they were in the Fiend Folio).