Head swap
There have been many trash movies over the decades that take inspiration from Frankenstein and other body horror movies. In those films, usually, body parts are sliced off and swapped onto other people in order to create monsters or zombies. But here we see that the head has been traded with two bodies.
Not really actually, the husband is hiding behind the tree with his wife as she puts her head back and he sticks his head out. It’s a funny little gag to play on anyone who does not know one of the oldest tricks in the book. Oh well, at least they are having fun in nature.