- Not to be confused with the song of the same name.
The Bill of Sale was an important document and a plot device in the original Disney film Pete's Dragon. it was a tattered old piece of paper given to the Gogans upon their illegal "purchase" of Pete - which in their twisted take on "law" made Pete their personal property by which to abuse and even enslave.
The beastly family carried the document with them wherever they went and threatened to use it in a court of law if anyone stood against them, even though they would likely kind of failed - the document itself was more a symbol of the Gogans' bullying but ultimately cowardly nature (reluctant to fight adults but willing to try and bully them into submission should they be opposed).
Ultimately,the Bill of Sale was destroyed by Elliot (who burned the document) - the Gogans were then forced to flee and without their Bill of Sale the family were unlikely to try and capture Pete again (combined with them now being aware of Elliot's existence and Pete being officially adopted by the kindly Nora).
It is unknown how the Gogans obtained the Bill of Sale or how weighty it would of actually been in a court of law but given the time-period the film was set in they likely got it from a child-slaver and it would of held little weight in a reputable court (since child slavery was illegal at that point).