You must absolutely never swallow batteries, as they pose a serious physical danger to the digestive system.

noli's read

The warning against battery ingestion is scientifically indisputable and crucial for the safety of our digestive system. Data from the National Capital Poison Center, derived from large-scale observational studies, demonstrate that batteries (especially button batteries) generate an electric current upon contact with moist tissues. This process causes rapid internal burns and major damage to the tissues of our digestive tract in less than two hours. The recommendations of the European Society of Gastrointestinal Endoscopy (which constitute an expert consensus) confirm the importance of strictly avoiding the introduction of these objects to preserve our digestive well-being. The creator's original presentation metaphorically illustrates this essential withdrawal for our bodily safety. This preventive advice is 100% validated by clinical research.

the sources

No named source held this one up — that absence is part of the verdict.