If you ever saw Lord of the Rings, you will know what an Ent is. It's basically a giant, sentient, walking tree that protects the forest it lives in from anything bad or malevolent, just like Trevenant, only that they have only two legs and two eyes like a human.
Aww! SO CUUTE! Phantump's my favourite too! The story behind it is really depressing though, and since I'm using the masuda method for a shiny, I think it means I'm killing random kids in the forest... But what can you do, y'know?
Ther's only one thing that bugs me about Phantump... it's Pokedex entry says that Phantump are ghosts of children who were lost in the woods... so does that mean, that every time you breed a Phantump... a child dies?