Beach Picnic is a Donald and Pluto short released 9 June 1939.
Donald Duck is singing happily at his beach picnic. After preparing the food, he tries to ride on a rubber horse, but gets repeatedly bounced off "Seabiscuit".
Donald then spots Pluto sleeping soundly on the shore, and decides to prank him by pushing Seabiscuit near him and mimicking a horse's whinnying. The mesmerized Pluto tries to chase Seabiscuit around some rocky reefs, but is scared when the horse bumps him from behind.
Pluto then frantically tries to push Seabiscuit into the water, to no avail. He angrily bites on the horse's muzzle, but its nozzle pops open, and the air inflates the dog. As the rubber horse goes completely flat, Pluto is sent flying in the air, crashing into a shipwreck on the shore.
Meanwhile at the picnic, some ants spy Donald's food. They call the other ants which swarm toward the picnic foods and carried them away. Donald sees the ants and frantically tries to chase them away. He places flypaper to catch them.
One ant tries to carry away a piece of cake, but Pluto spots it and follows it as it tries to escape. The ant wisely goes beneath the flypaper, but Pluto gets his nose gets stuck on it, and then his paws, his ear, and his butt. Donald laughs hysterically, that is until Pluto's struggle sends him backward, sticking the flypaper to Donald's butt too.
Donald rants as Pluto runs around swinging him in circles frantically. When Donald comes unstuck he flies toward the picnic and rolls over the rest of the flypaper, wrapping himself up in it like a mummy. Pluto, with an unexpected joy, jumps onto him and licks his face.