Glow sticks pose several risks to pets during Halloween. When chewed or punctured, they can leak a liquid that, although not highly toxic, can cause irritation to the mouth, throat, and stomach, leading to drooling, vomiting, and discomfort. The size and shape of glow sticks also present a choking hazard or could lead to gastrointestinal obstruction if swallowed by a pet. It's advisable to keep these items out of reach and monitor pets closely during festivities to prevent any accidents or ingestion.