A movement speed decrease effect causes a creature to move slower than normal. This is usually measured as the percentage lost from the base movement rate. In many ways, a movement speed decrease effect resembles being encumbered or being unable to run due to detection and/or stealth modes. All of these share the same icon and are described on the character sheet as "movement speed decreased", but there is an important distinction to be made — of these, only the effect is blocked by freedom.
Movement speed decrease is distinct from slow, as being slowed incurs penalties in addition to slower movement.
Common sources of a movement speed decrease effect include the grease and web spells.
See also: Movement speed increase