Magic is a knot or spell that has effects on the heart and body, it causes the heart or body to become sick, it can kill a person, it separates a man and his wife, and destroys family ties.
Magic and its existence are confirmed by the Qur'an and Sunnah and is agreed upon by the scholars. It is a reality and a truth, and it affects a person only by Allah's will.
There is a consensus among the scholars of Tafseer that Surah Al-Falaq was revealed because of Habeebbin Asum who did magic on the Prophet (saws).
Symptoms of black magic: