Place it at the reveal beat itself, not over gameplay before it. Lead in with the dramatic dun dun dun sound effect for the build, then use this clip, and follow with the among us role reveal sound when the impostor twist needs a second punch afterwards.
About this sound
This is a 2.5-second remixed laugh from Sonic.EXE, with the voice stretched by echo so it rings out instead of ending flat. It feels taunting and unsettling, like a villain enjoying the scare a second too long. It comes from the fan-made evil Sonic character that spread through creepypasta stories and fan games.