The worm doesn’t resemble the typical worm that might come out of a human, so the reader probably doesn’t need to inform the last person that used her bathroom about it. However, if she is nervous about it, there is no harm in letting them know.

Based on the photo our reader sent in, we think this is a millipede. Since our reader didn’t mention the presence or absence of legs on this creature, we can’t be totally positive this is a millipede. However, millipedes sometimes tuck their legs into their bodies. We believe that is the case in this photo, and that our reader is dealing with a millipede. Millipedes are common household pests that require moisture for survival, so it is possible they might end up in a toilet.

Since our reader only discovered a single creature, we recommend she put it outside and hope that more don’t return. If more millipedes, or other pests, appear in the toilet we recommend she contact a plumber to see if there is something wrong with the pipes that is allowing these intrusions.

To conclude, our reader found what we believe to be a millipede in a toilet. We hope that she is able to get rid of it and be free of these creatures.