[He looks away for a moment and glances at his right hand.]

Well, I actually don't know. I can tell up the worse that's happened was a sickness called Overgrowth. It gets inside you and takes root based on what you aren't 'emotionally honest' about.

You either confess to those things or the flowers grow inside you. When it reaches your head it's, [He grimaces and his face drains a little of color. It still makes him ill to think about it.] let's just say you die in a bad way.

That's not the only instance of our heads being messed with. There's a long list.