This page contains a detailed description of unlocking the bronze trophy called "Crash Cubed" in Crash Bandicoot 2: Cortex Strikes Back for PlayStation 4. This trophy is awarded for making an uncontrolled flight that ends with Crash's death.
You unlock this trophy in the Bear Down. The portal to it is located in the Sewer Warp Room. This stage involves traveling on the bear cub's back. Continue traversing and avoid all obstacles until you are near the group of natives busy raising and lowering a large ice block. You can see them in the picture.
Move as far to the left as possible and make a jump at the last moment. As a result, the bear cub will hit the ice block and Crash will start an uncontrolled flight (above image).
The protagonist has to land in the air hole and freeze to death (above picture). This death unlocks the trophy.