[RPG] Can some monsters grapple as an opportunity attack

dnd-5egrapplemonstersopportunity-attack

In 5e, I realize that you can not grapple as an opportunity attack, as the grapple is an action and the opportunity attack is a reaction.

However, am I correct in assuming that some monsters can grapple as an OA?

Opportunity Attack

You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature.

Let's use a Vampire Spawn as an example. Listed in its attacks is using its claws:

Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 8 (2d4 + 3) slashing damage. Instead of dealing damage, the vampire can grapple the target (escape DC 13).

Since the claws are considered a melee attack and they have this extra ability to grapple instead of deal damage, I would think they could be used for an AoO.

Just wanted to see if anyone can point out something I may have missed. Thanks!

Best Answer

Yes, as long as the grapple is delivered by a melee attack that doesn't require some other specific Action

The sage advice compendium answered a similar question to this one about spell attacks. In part, it talks about monsters making spell attacks as opportunity attacks. The clarification notes that:

A few monsters can make opportunity attacks with melee spell attacks. Here’s how: certain monsters—including the banshee, the lich, and the specter—have a melee spell attack that isn’t delivered by a spell. For example, the banshee’s Corrupting Touch action is a melee spell attack but no spell is cast to make it. The banshee can, therefore, make opportunity attacks with Corrupting Touch.

From this, we can determine that a monster can use any of its melee attack options when it makes an opportunity attack, as long as they don't require some other action to use (like how the grapple or shove attacks in the PHB require the Attack action).

So, the vampire spawn can use its claw attack as an opportunity attack since it's a melee attack that is not mandated to be delivered by some other specific action. The claw attack itself can grapple a target if it hits instead of dealing damage. And since opportunity attacks do not specifically override any on-hit effects from making an attack, the vampire spawn can elect to replace the damage roll with the grapple.

Related Solutions

[RPG] Can you grapple a creature as an opportunity attack

As Miniman's answer points out, you cannot grapple as an opportunity attack because an opportunity attack does not give you an Attack action. However, your situation doesn't actually call for an opportunity attack. Instead, it sounds like you had readied an action. From Basic Rules page 72:

Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn so that you can act later in the round using your reaction.

First, you decide what perceivable circumstance will trigger your reaction. Then, you choose the action you will take in response to that trigger, or you choose to move up to your speed in response to it...

When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one reaction per round.

When you ready an action, you declare that you intend to do something out of your turn in response to something specific happening. For example, you can ready an action by saying "If an enemy comes through that door, I will fire an arrow at them." If an enemy does come through the door, you can then immediately use the readied action and shoot them.

Therefore, if you state on your turn, "I want to grapple the gnome if he tries to get past me," and you have not taken another action on your turn, you would be able to grapple the gnome as he moves past you. If the gnome doesn't try to get by you, the action is wasted. You can also choose to ignore the trigger and take an attack of opportunity as your reaction instead.

Keep in mind that you must declare a Ready action on your turn. Ready actions are actions, like attacks or casting spells. If your turn had already passed when you declared you'd grapple the gnome, your DM would be right in ruling that you can only make an attack. However, if you declared it on your turn, and hadn't already attacked or acted, your DM should have allowed you to grab the gnome.

[RPG] Does the Goblin Boss’s Redirect Attack provoke an opportunity attack

Yes, if the second Goblin is not within the Reach of the thing making the opportunity attack

It seems a bit weird, however the criteria for triggering an opportunity attack are:

You are moving out of the reach of a hostile creature
This movement is from one of your Actions, Bonus Actions, Movement or Reaction
You have not taken the Disengage action
You are not Teleporting

For this question we can discount Point 4, as the Goblin Boss can't teleport.

We'll also ignore Disengaging for now.

For Point 2, the movement is by the Goblin Boss' Reaction, which fulfills that criteria

For Point 1, if the swapping with the second Goblin does not cause the Goblin Boss to leave the Reach of any hostile creature, it will not trigger an Opportunity attack. In the diagrams below, the first set of movement will not trigger an opportunity attack, while the second set will.

EG    ->    EB
B           G


EBG   ->    EGB

E - Enemy; 
G - Goblin; 
B - Goblin Boss

Note that wherever the second Goblin is moved from, it does not trigger an Opportunity attack from anything as its movement is forced by the Goblin Boss.

As for using Disengage (via Nimble Escape), it only stops OAs for the rest of your Turn, not the entire Round.

So, if someone had Readied an action to hit the Goblin Boss when the Boss did a specific thing, then the Goblin Boss did that thing on the Boss' turn, and in Reaction the Boss used Redirect Attack, that would not trigger an OA, wherever it moved, as it is still the Boss' Turn so Disengage is still in effect. But normally, Disengage would not help for this.