mic drop
1. verb To dramatically drop one's microphone (or, often, to mimic such a motion) after a particularly decisive or impressive performance, action, or statement. Did you see him mic drop after that rap battle?
2. noun A decisive or impressive statement or action. You were so confident during your presentation that the last slide was like, boom, mic drop! I think the partners were very impressed. That dunk was the mic drop that ended the series.