This is how Starlight, Trixie, Thorax, and Discord meet the Witch Doctor goes in My Little Pony: Return of the Witch Doctor.
Witch Doctor: Oh, you're those two unicorns, changeling, and draconequus I've heard so much about. Don't seem too valuable to me.
Starlight Glimmer: We are Starlight Glimmer.
Trixie Lulamoon: Trixie Lulamoon.
Thorax: Thorax and Discord.
Discord: And don't you...[tries to tackle him, but the Witch Doctor jumps and discord hits the wall]...forget it.
[Witch Doctor smiles]
Witch Doctor: The Quaza has changed me. You girls and boys are with me now. You have nothing for me, except your magic. [laughs evilly] By answering my distress call, you've provided me with a vehicle so I can escape this dying castle.