The Spiderwick Chronicles ending explained (spoilers)

[RafaelDet 0]

Mulgarath chases Jared (Freddie Highmore) to the top of the house and to try and get Arthur Spiderwick's book he transforms into a crow and Hogsqueal eats him. The Grace family takes Lucinda back to her father's house and they're visited by Arthur Spiderwick. He tells his daughter Lucinda that he can't be with her because the elves will no longer surround him and he'll turn to dust. Lucinda goes with him to to the land of elves and she becomes younger (the same age when they were separated). The Grace family continues to live in Arthur's house...

[carla]

Max drills the mark on his head (could be symbolism.) The mark that Max drills out is his ability to understand Pi, which, based on other examples we have seen, would lead him to his death. He chooses to live and not understand Pi. After that the little girl asks him some math questions. He just smiles and says I do not know.