According to narrations from our Imams, a Jewish man named Lubaydeb Na'asam crafted a magic spell to harm Prophet Muhammad (peace be upon him). Satan had a hold on this Jewish man, and he created a spell by tying different knots in threads and reciting whispers over them called "nafasatil feluqad". Lubaydeb then tied this thread around a branch of a palm tree and threw it into an old abandoned well outside Medina. The next day, the Prophet fell sick, and Jibrael (peace be upon him) came to him and informed him that it was due to the spell cast by Lubaydeb Na'asam. 

Jibrael (peace be upon him) instructed the Prophet to send someone to retrieve the spell from the well. Imam Ali (peace be upon him) took on this task and was successful in retrieving the spell. When he arrived, the Prophet recited the "surah al-muawzateen" i.e. Surah Naas and Surah Falaq to dissolve the magic spell. Imam Ali (peace be upon him) took the knots out one by one as the Prophet recited the "muawzateen", and every time they recited it, a knot would become untied until all the knots were opened. After the knots were untied, the Prophet was cured of his illness and returned to good health.

This story, documented by Imam Jaafar Sadiq, is authentic, and it serves as a reminder to us that magic spells exist and can have serious consequences. The aim of the shaitan (Satan) in this case was to cause harm to the Prophet and annoy him, and it shows that the effects of magic spells can be temporary, like a vision problem, or more severe. However, according to the narration, the spell only affected the eyes and private parts. We need to be aware of the potential harm of such spells and protect ourselves by using tools like the "surah al-muawzateen", "surah al-tawhid", "surah al-fatihah", "surah al-kafirun", and "surah al-qadr". These are gifted to us by Allah as a protection against magic spells, and we should use them to keep ourselves safe.