Terrain hazards and obstacles are elements, commonly found in game worlds, that block or hinder movement or cause damage to characters. Typically hazards cause some form of harm while obstacles merely restrict movement. Terrain hazards could be traps, but often they are naturally occurring terrain features or man-made objects.
When designing terrain hazards, consider the region or biome, and the local terrain itself. Mysterious jungles may have quicksand, uncharted rivers may have piranha pools, seas may have treacherous waters and ship graveyards, and fantasy fire swamps may have fire spouts.