Place this clip at the impact point in your edit, after the setup shot and before the reaction. Follow it with the Mortal Kombat Fatality for a knockout finish, or precede it with the Metal Gear Alert Sound when a trap is spotted first.
About this sound
This clip is the Thwomp slam from Super Mario 64, a short percussive impact lasting about a second and a half as the stone enemy drops and hits the ground. It feels heavy, abrupt and cartoonishly threatening, like sudden pressure landing all at once. It comes from Nintendo's Super Mario 64, released in 1996.