Fool Me Once

I thought this was a fun idea where two trick-or-treaters try to scam an old couple out of candy but end up in trouble. The two actors who play the old couple do a nice job throughout, even as their characters change. The two kids do not do a great job being convincing and this short would have benefited from better performances.

The big issue is the story. Is this a serial killer villain? Is it a monster? How are the old couple involved? What did the twist end mean? I feel like the creators had some ideas but didn't exactly know how to end the movie.