The obstacle is a triangular prism on an axis above the waters that competitors must first jump on too and then scramble to the other side before tipping over into failure. The Front side is weighted heavier, making speed a bit necessary. As it starts to lean forward, you are pretty much in the clear. However, a nice, soft jump is needed so you don't push the prism, with yourself on it, down into water.
The Prism Tilt took out almost exactly 75% of competitors, not bad at all for a Stage 1 obstacle.