Grappled

  • A grappled creature’s speed becomes 0, and it can’t benefit from any bonus to its speed.
  • The condition ends if the Grappler is Incapacitated(see the condition). 
  • The condition also ends if an Effect removes the grappled creature from the reach of the Grappler or Grappling Effect, such as when a creature is hurled away by the Thunderwave Spell.


See the  Grapple action  

Causes

Common Causes: Players wrestling with their enemies, claws and jaws of certain creatures like Giant Crabs and Grell,

Affected Groups

Why it matters to players: If you have a high Athletics score, you absolutely must make use of it here. It may not sound like a lot if your only concern is pummeling an enemy to death, but there are some creatures where simply swinging a greatsword is not the most helpful thing you can do. By making an Athletics check, which can replace one attack action if you have the Extra Attack feature, contested by the target’s Athletics or Acrobatics you can Grapple a creature one size larger than you or smaller.
  It will require you to have one hand on the creature and you will have half movement, but the creature comes with you. It takes an action on their part to break loose or the truly bold might try to shove you away, but if a creature is massively out-damaging you, this is a great way to tie up their turn. This is particularly brutal when combined with the Shove Prone (more on the prone condition later).
You can drag enemies into the spell caster’s area of effect, ground flying enemies, or even drag a target away from their allies where you can introduce them to the business end of your longsword. If they’re not strong or slippery, teleporting out or blasting you away is their only good option.   PS: You can only dodge if you have movement. The Grappled condition negates the Dodge action.
Why it matters to DMs: Grappled is another effect that is usually augmented by other effects or is a rider on an attack. While your creatures can benefit from all the same effects the players can, I would also advise the usage of this to bring players into a tense 1-on-1 conflict with a villain that can make them feel targeted and singled out for being so dangerous. Infamy is a good feeling as a player.   Word of advice about flying creatures, they do not have a penalty beyond the standard half movement for flying while Grappling a target. This means villains can use flying creatures for extraction or abducting heroes a lot easier.

https://halflinghobbies.com/every-condition-and-how-to-use-them-in-dd-5e/#Blinded