In addition to enemy incursions, there are other dangers such as the marauding, gigantic sandworm, capable of swallowing vehicles and infantry whole but blocked by rocky terrain. The player can only build on rocky terrain and must build concrete foundations to avoid deterioration of the structures due to the harsh weather conditions. Structures will still gradually decay over time regardless of the presence of those concrete slabs. Although the concrete saves repair costs in the long run. Spice fields are indicated by orange coloration on the sand, darker orange indicating high concentration. Some spice may be concealed as bumps on the terrain (a "spice bloom") that become spice fields when they are shot at, or when a unit runs over them (the unit is destroyed in the ensuing "spice blow").