There are sudden screams in the audience of bidders, confusing the auctioneer somewhat until he sees their motions of pointing behind him. He turns his head right in time to see your large mouth's lips slip over the microphone in his hand and pull it from him, to which he responds by falling backwards in a surprised yelp. You can see the snipers adjusting their aim, but since you acted calmly and slowly without hurting anyone, they have not yet shot.
You let your long tongue poke out between your lips and engulf the small voice-enhancer, before swallowing it down. At once, the massive opera-hall-like room is filled with the ambience of your innards... slow pulsating sounds from your single long gut, the slow phase of your two hearts drumming to each other, and finally the gurgling sound of your massive stomach beginning to work on your recent meal.
However, in the background can also be heard the faint and weak whimpers of the unconscious servant, whose pain and nightmares is causing it to mumble in its native tongue.
Only when you hear that the item has reached what you intended for it to do, you continue with your plan.
Laying down in a way that shows off the bulge on your long body, let out a hiss before flattening yourself! The same technique you use for flying by pulling in your many belly-muscles, which causes a the sound of someone stepping in a bucket of meat-covered Legos to fill the echoing room, as the ribcage and several other bones are shattered in an instant!
But you do not let it rest there, for you curl up slightly and look the crowd of slavers and bidders dead in the eye. And with a threatening hiss, you tighten the curl on your body, letting the sound of the servant's shattering spine fill their ears.
You then lay down and await silently for the bidding to commence, leaving both the terrified audience and auctioneer utterly silent for a minute or two more, until a stage-worker manages to remotely shut down the microphone you swallowed and deliver the man on the stage a new one...
