“Can you help tell us what this is?” asks this reader in her submission regarding the thin, black worms pictured below. “And if it is common, or coming from one of us? And any possible ways of stopping worms in the toilet? My mum bleaches frequently and is super clean.” Despite our reader’s short submission, there are a lot of questions to be answered here. Firstly, we can definitely help our reader in identifying the worm-like creature pictured below. We think this is possibly a horsehair worm. These worms are somewhat common, though they are more common in nature than in people’s homes. They would not be coming from our reader or her mother, despite being parasites.