The Invader is Growing!

It is unfortunate I have to show you this, but I do. One Penis Shroom is out of control, while the other one is dying off. mk suggested the possible presence of Smurfs, but I don't think so. If this were their house, they would have to take the elevator up the very skinny shaft...

Okay, I will stop. I just wonder if it is edible. Any specialists out there that could tell me how poisonous this one is? Better yet, why it is growing in my Shamrock plant?