Preventacles

 were a brand of psychic spectacles. They were visually identical to regular, black-framed sunglasses but had the added ability to allow the wearer to see events that would most likely happen in the near future of their field of vision. Although ostensibly created to allow wearers to prevent potential accidents and incidents, hence their name, the type of short-term clairvoyance utilised ended up causing just as many casualties and even led many users to cause the incidents they were trying to prevent.

After these cases, the Preventacles were banned in the Five Galaxies and a Product Safety Recall notice was put out for them, allowing affected customers to receive a refund or a free pair of Telepathy Socks.

History
Upon landing at a beach with the Thirteenth Doctor and Yaz, Dan Lewis picked up a pair of Preventacles from the Doctor's TARDIS, unaware of their true nature. This caused him to first witness Yaz supposedly drowning (in reality attempting to swat some wasps a few minutes later) and a man falling off a cliff, which Dan nearly caused when he went to interject. Later, the Doctor admitted her mistake at leaving them in the TARDIS and Dan discarded them on the beach, unaware they were predicting that the time travellers would soon battle a giant wasp. (COMIC: Fear of the Future)