Prone

The creature is lying or crawling down on the floor :

Its only only movement option is to crawl.

It has Disadvantage on Strength and Dexterity Saving Throws.

Attack Rolls against a Prone creature have Advantage if they're made within 3 meters of the creature. They have Disadvantage otherwise.

If the creature gets knocked Prone unwillingly while they are maintaining an idiom, the idiom stops being maintained.

To end the condition, the creature needs to stand up by consuming half of its maximum Movement resource.