They don't really have spells. They talk about making life difficult for the master of the ship the Tiger, the guy whose wife doesn't like sharing chestnuts. They predict Macbeth and Banquo's future. They summon up spirits who make further predictions. I don't think these count as spells.
In Macbeth, the three witches are referring to Macbeth when they say "Something wicked this way comes." They are speaking about Macbeth as he approaches them, indicating his dark and villainous nature.
King of Scotland the witches also say that he will become the thane of cawdor
Macbeth
The witches greeted Macbeth with chants of "All hail, Macbeth! hail to thee, Thane of Cawdor!" and "All hail, Macbeth! that shalt be king hereafter!" These prophecies fueled Macbeth's ambition and desire for power.
Macbeth. She said "Hail, Macbeth!" In fact all three witches say exactly the same thing.
The witches say, "By the pricking of my thumbs, something wicked this way comes." In many depictions of witchcraft, blood must be spilled in order to activate a spell. Magic users in fiction will often prick their fingers in order to draw blood for a sacred ritual. The witches in Macbeth are planning a great mischief, and they draw "something wicked" to them through their spells, hence the pricking of their fingers. Macbeth himself becomes this "something wicked."
banuqul
No they don't but there are people out there . Some say its just made up . But where did they get the idea? Speculations have begun and there will be a documentary on witches and spells . To find out more google witches and spells.
Macbeth is suggesting that the witches bring corruption wherever they go and that anyone who believes in them is also doomed. By aligning himself with the witches and putting his trust in their prophecies, Macbeth is essentially acknowledging his own descent into darkness and the consequences of his actions.
Macbeth killed banquo. Because Macbeth heard the witches say he will also be king. so Macbeth saw him as a threat to the throne and lets just say did something bad to banquo (killed him)
"Hear his speech, but say thou naught."
"Hear his speech but say thou nought."