Odd object lifting. Do eight year olds count? There is only the one of him, so he is quite unique, if not necessarily odd.
Isn't the principle of progressive overload often attributed to some story about the 6th Century BC Greek Olympian Milo of Crotona who started out by lifting a calf and as that calf grew and became heavier he would overload his muscles and become stronger.
However, some say that the protein myth, about the need to eat meat and huge amounts of protein to get strong, can also be traced back to Milo, who consumed 20 pounds of meat a day. Milo reportedly carried that ox over his shoulder through the stadium at Olympia and then killed him with a single blow to the head and proceeded to slaughter him and cook his flesh.
Damn, this post really took a negative turn. Sorry about that.
Anyway, keep lifting him and as he gets bigger you'll become stronger.