It's MGM with puppies, so you can be pretty sure of saccharine cuteness throughout-- and yet this rather unfocused piece turns uneasily dark... Two realistic small boys and their sister come downstairs on Christmas Eve to see what Santa's brought, followed by Black Pup and Brown Pup. Santa seems to have brought enough to stock an entire toy store and half a pet store as well!
The pups react quite naturally when encountering all these new objects, and I thought Black Pup's bristling at a large stuffed dog particularly amusing in a mild way. The little girl exclaims over the new doll that says 'Mama', while the boys wind up a train, ride a trike, and then --fatefully-- wind up a toy tank, which brings it to conscious and malevolent life.
At this point the cartoon seems to have been taken over by someone new; the children disappear, presumably having returned to bed, and leaving the pups in possession of the field. Brown Pup is discovered to have dismembered the 'Mama' doll, and manages to swallow the 'Mama' device, with consequent schtick. The vicious toy tank pursues and attacks anything that moves, murdering two other live toys-- where will it all end?
