It's important to identify whose side a potential enemy is on before you take any hostile action, since they may turn out to be on your side.

For some fun with this, have an allied messenger or something approach the heroes to deliver some important news. But make the messenger look like an enemy. Maybe the king has hired an unusual good-aligned goblin to serve as a messenger or something. (Actually, that's a pretty good way to make sure your messenger doesn't live very long. But still, you don't need to worry about little things like logic.)

Transcript

R2-D2: So we're facing a complete rout in space, and overwhelming odds down here too.
R2-D2: Right, unleash hell, Threepio!
[SFX]: < bizz doodle-dooby po-fipgi-doip-bedoop >
C-3PO: My forrowers! Now is the chance! Riquidate the Empire! Seize their assets!
Bunker Commander: What's that protocol droid on about? Is it one of ours? Go grab it.
{troopers surround the droids}
Clone Trooper: Excuse me. Are you on our side, or the Rebels'?
C-3PO: I'm on all sides!
C-3PO: Forrowers, attack!
{Ewocs attack the troopers}
Ewoc 1: For the profit!!
[SFX]: Crunch!
Ewoc 2: For the profit!!
[SFX]: Whack!
Ewoc 3: For the profit!!
[SFX]: Thump!