Macbeth - Act 3 Scene 5

A heath. 

Thunder. Enter the three Witches meeting HECATE

First Witch
Why, how now, Hecate! You look angerly.

Hecate is a goddess of witchcraft, and clearly outranks the original Witches. There is little indication of how she is to be portrayed, though there is a great deal of room for spectacle in her entrance and exit.

The "wayward son" may be Macbeth, though that seems out of place with the play's events. It's not clear exactly what the basis of Hecate's argument is, though she's clearly unhappy with having been left out of the proceedings.

HECATE
Have I not reason, beldams, as you are
Saucy and overbold? How did you dare
To trade and traffic with Macbeth
In riddles and affairs of death;
And I, the mistress of your charms,
The close contriver of all harms,
Was never called to bear my part,
Or show the glory of our art?
And, which is worse, all you have done
Hath been but for a wayward son,
Spiteful and wrathful, who, as others do,
Loves for his own ends, not for you.
But make amends now: get you gone,
And at the pit of Acheron
Meet me i' the morning; thither he
Will come to know his destiny.
Your vessels and your spells provide,
Your charms and every thing beside.
I am for the air; this night I'll spend
Unto a dismal and a fatal end;
Great business must be wrought ere noon:
Upon the corner of the moon
There hangs a vaporous drop profound;
I'll catch it ere it come to ground;
And that, distilled by magic sleights,
Shall raise such artificial sprites
As by the strength of their illusion
Shall draw him on to his confusion.
He shall spurn fate, scorn death, and bear
His hopes 'bove wisdom, grace and fear;
And you all know, security
Is mortals' chiefest enemy.

Music and a song within 

The mention of the "little spirit" sitting "in a cloud" may indicate that Hecate is meant to exit flying, lifted into the air by wires or a similar device.

Hark! I am called: my little spirit, see,
Sits in a foggy cloud, and stays for me.

Exit

First Witch
Come, let's make haste; she'll soon be back again.

Exeunt