Sputnik's Guide to Life on Earth by Frank Cottrell Boyce 
 
Then one day Prez answers the door to someone claiming to be his relative. This small, loud stranger carries a backpack, walks with a swagger and goes by the name of Sputnik. The family all think Sputnik is a dog and chaos is unleashed as suddenly household items come to life – like a TV remote that fast-forwards people and a toy lightsaber that entertains guests at a children's party, until one of them is nearly decapitated by it – and Prez is going to have to use his voice to explain himself.

As Sputnik takes Prez on a journey to finish writing his guidebook to Earth called Ten Things Worth Doing on Earth, each adventure seems to take Prez nearer to the heart of the family he is being fostered by, but they also take him closer to the day that he is due to leave them forever . . .