The Vault Of Winter, Module 6: Behind The Curtain
The revelation should be handled with as much theater as can be managed; slow, knowing nods or even jazz hands are recommended. To give your players a real thrill, try placing our wholly custom DMs Flashlight (DMFL03) below the chin, and, once there, turning it off and on.
Lord Wyntyr rolls incredibly deep, with a posse of 1d4+1000 utterly devoted elfs. These elves are immortal, so long as they are never harmed. Or jostled. Or touched at all. They can bake cookies until the peal of the Last Horn, but if they drink a glass of milk too fast they explode in a confetti puff that smells vaguely of peppermint or cinnamon. That scent is their literal spirit; to smell it is their final death.
Lord Wyntyr can Throw Elfs as a free action, so there is no limit to the number of elfs he can throw. A five by five square can hold up to a hundred such creatures, piled atop one another in teetering, festive columns. This means that on turn one, he is throwing over a thousand elfs. We didn't have a lot of time to test this mechanic, as the module needed to go to print to take advantage of the Holiday theme. I'm sure it's fine.