BFG uses dreams from his collection .
BFG creates a nightmare , blows it into the Queen 's bedroom , leaves Sophie on the Queen 's windowsill to confirm the dream , and retreats into the palace gardens , re-emerging when Sophie calls to him .
Using dreams from his collection , BFG creates a nightmare , blows it into the Queen 's bedroom , leaves Sophie on the Queen 's windowsill to confirm the dream , and retreats into the palace gardens , re-emerging when Sophie calls to him .