I was wondering what the rules say about dodging while prone. I couldn't find anything from the PHB. I would imagine that rolling out of the way of attacks is possible but it would be kind of slow so I don't know how to rule it.
In my situation a cleric used Turn Undead and a frightened skeleton that was in a corner as far away as possible from it's source of fear so it's only option was to dodge. It was knocked prone and in a corner so I just ruled it so that it couldn't dodge.
Best Answer
A Prone Creature can Dodge
Nothing in the rules specifies that a creature cannot take the Dodge action while under the effects of the Prone condition.
The Prone condition (PHB, p. 292) states:
And the Dodge action (PHB, p. 192) states:
What would happen in this scenario is that any melee attackers against the prone dodging creature would not have advantage or disadvantage, while ranged attackers would have disadvantage.
There are additional rules on "Being Prone" (PHB, pp. 190-191), but it is mostly describing how to move while prone, and does not forbid the use of any actions, including the Dodge action.
(Incidentally, I'm imagining it would look like Samwise trying to dodge Shelob's stinger from the Lord of the Rings: The Return of the King film.)