The word "splat", but with the "Ker-" prefix, thus way more awesome.
Example man: I walked down the street, tripped, and KERSPLAT!
Lil' Guard Duck from Pearls Before Swine: Dearest Pig, These are dark days. Days filled with empty bottles and empty hearts and an abundance of unwanted clarity. For I now see that to love is to leap an unleapable gorge and hope that a rope will be thrown from the other side. When it works, it's a spectacular feat of daring. And when it doesn't, it's kersplat. Kersplat.