A lonely boy's everything. His parents, siblings, pets, house, etc. He walks his turtle to Airmail and hangs out there all day long. The boy enters his turtle in dog competitions for agility, frisbee, and obedience. His turtle greets him every time he comes home and sleeps on the end of his bed at night.
(Not to be confused with tortoise.)
Boy: I love you, turtle!
Boy: I know, now let's go get some ice cream.