Though it may seem like a good idea to trust a giant pink dragon who says he can save you from the end of the world, it is not a good idea because Hubert is a known bibliophile. He has been caught on several occasions, burining libraries and other holders of books, namely Borders, which explains why they went out of business so fast.
Along with being a bibliophile, Hubert is also a dangerous schizophrenic with multiple personalities disorder that will eat you if you take him up on his offer of protection from the end of the world.
If Hubert approaches you with an offer of protection, well first of all it’s not that hard to miss him, and secondly, you pretty much stand no chance of running away once he sees you because he will eat you. Or one of his other personalities will eat you.