Poor Papa (found Oswald the Lucky Rabbit animated short; 1927)
Poor Papa is the first Oswald The Lucky Rabbit short, created in 1927 by Walt Disney. In the short, Oswald gets a visit from a stork who continues to drop babies into his chimney at a rapid pace.
There are only three copies known to exist. The first copy was sold in 2001 for a decidedly small fee of $100; the second copy was sold for £170 and the third copy was sold in 2014 for $7,500. None of them have been ripped for the Internet so far, and the cartoon was not aired on television because it, allegedly, "wasn't high-quality enough".
It seems that the copies may include only 3 minutes of the short (a bit less than half of it), so if this is true then rest of the short may be permanently gone.