[RPG] What balance problems arise by allowing grappling as an option for an Opportunity Attack

dnd-5egrapplehouse-rulesopportunity-attack

In our last session (with me as the DM), a creature was surrounded by the party and was trying to flee. She cast Levitate on herself to try to float up and get away. As she was going up and thereby out of reach of several party members, they each got an Opportunity Attack against her. Several of them wanted to use this opportunity attack to try to grapple, holding on to her to keep her from getting away, rather than a more traditional melee attack. I wasn't sure whether this was an allowed way to take an Opportunity Attack, but the scene of her floating up with one of the player characters grabbing onto her legs as she went up was pretty neat, and I figured via Rule of Cool that I should just allow it. And it did lead to a really fun encounter, with the character dangling off the legs of this creature in midair trying to slap some manacles on her to prevent further spellcasting.

Now, after the session, I figured I'd look up the actual rules, and sure enough by the book Opportunity Attacks only allow for a melee attack, not a grapple. So I guess my question is, what issues might I encounter if I maintain this precedent of allowing a more generous set of actions as Opportunity Attacks? It sure seems that trying to tackle or trip somebody as they run past you could make for some fun scenes, and it feels more "realistic" in some sense than only allowing for a melee attack.

I'm a relatively novice DM, and am thus hesitant to go very far outside of the standard rules.

If I just allow for this — substitute in a Grapple for a melee attack during an Opportunity Attack — will this create balance problems?

Best Answer

This should not cause a balance problem if you confine it to Grapple.

Grappling

When you want to grab a creature or wrestle with it, you can use the Attack action to make a special melee attack, a grapple. If you’re able to make multiple attacks with the Attack action, this attack replaces one of them. (Basic Rules p. 74)

A couple of points on using a grapple attempt versus a weapon attack:

  1. The creature takes no further damage (and is thus still alive to do stuff next turn/round)
  2. The Grapple attempt may fail, just as any Opportunity Attack may fail.
  3. The character trying to Grapple Must Have A Free Hand to do so! (A sword and shield, or two weapon wielder, won't have a free hand for their reaction, but they can drop one of the held items).

Action economy wise, the player had a reaction to spend and an attack available. Making "a special melee attack" versus "making a melee attack" is a subtle distinction. It is still "making a melee attack" that does not damage, and cannot critically hit.

If you are playing in a game where characters are not using feats, it's a way for martial characters to get a little more flexibility in the action economy.

Recommendation

Keep doing this for the next few levels, restricting it to the grapple action as "a special melee attack." If it gets out of whack it should become evident during play. Make sure your players are informed that this will be "play test" to see how this fits. Make sure enemies try this as the occasion arises. ( And see how your players react to that).

Leave Shove out of this for the time being

Why? The enemy is already moving out of the way. If you are doing battle near ledges you can see how a shove off of the ledge might be a more powerful effect (falling damage can ramp up rather quickly). However, if you are happy with how Grapple works out, consider adding this "special melee attack" as a reaction ... but beware of the can of worms.

Shoving can lead to moving a creature, or knocking them Prone. Prone, as a condition, opens up attacks with advantage for your team, etc, and applies some other effects. While it too can fail, and does no damage, its effects are more pronounced than Grapple's.

Rule of Cool

As an aside, love the rule of cool / rule of fun approach you took in-play to make a ruling that was fun, and then looked into details later.

Related Topic