A YouTube video shared by ViralHog shows a table laden with full-sized candy bars alongside a note: "Help yourself but be considerate!"
The video's description added: "We figured a group of kids would probably end up taking all of the candy at one point during the night, but everyone was really considerate...until this upstanding mother came to save the day."
Footage shows kids dressed in costumes helping themselves to a few pieces of candy before the woman, dressed as a bunny, grabs bars by the fistful.
When she leaves, a young boy runs up to the table - and stops as he realizes all the candy is gone.
"World's Best Mother," reads a certificate showing the mom's face at the end of the video.