That is known as an "impact" sound
I can't listen in detail (on my iPad) but the key elements are...
The spooky build up helps to create the impact
The actual "impact" sounds like a mix of a vocal "oow" from JK, a cymbal hit, the first hit on that lovely squelchy bass and the first hit of the drums and tambourine
It could be my IPad speakers but the whole impact sounds very "bright" (IE high mids and high frequencies being emphasised on the cymbal, vocal, tambourine etc.), which really contrasts with the spooky synth build up which is very low and moody - so I think this also creates impact
If I were doing this I would also mix in a (at a very low/subtle level) an actual "impact" sample such as breaking glass, an explosion, a car smash, a synth hit etc. which will help add a bit more depth
I hope this helps steer you in the right direction and I would love to hear the end result