6
\$\begingroup\$

I know that infestation movement does not provoke opportunity attacks. However, I have a different question:

Does the movement caused by the infestation spell trigger the extra damage of booming blade?

The description of booming blade (SCAG p. 142) states:

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.

And infestation (XGtE p. 158) says:

You cause a cloud of mites, fleas, and other parasites to appear momentarily on one creature you can see within range. The target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move and its speed is at least 5 feet. Roll a d4 for the direction: 1, north; 2, south; 3, east; or 4, west. This movement doesn’t provoke opportunity attacks, and if the direction rolled is blocked, the target doesn’t move.

\$\endgroup\$
9
\$\begingroup\$

No. Movement forced by a spell is not willing movement.

"Willing movement" (and being "willing" in general) is never defined in the rules, though it's referenced in spells like booming blade (SCAG, p. 142). Thus, since it's not a defined game term, we default to the natural English definition of the term.

According to Dictionary.com, "willing" means "disposed or consenting; inclined". However, the movement from the infestation spell (XGtE, p. 158) is forced by the spell on a failed Con save; the target has no choice about whether to do it, so it's certainly not doing so of its own volition. As such, it seems clear that movement forced by such a spell is not willing.


Jeremy Crawford supports this interpretation in an unofficial April 2016 tweet in which he addresses a similar question about the dissonant whispers spell and its interaction with booming blade:

Would you take damage from the second part of Booming Blade if you fail a save against Dissonant Whispers and move away?

Booming blade hurts you if you move away willingly. Dissonant whispers forces you to move—doesn't trigger BL.

but if they move after whispers in their turn (to get back into melee, for example) that counts, right?

Yes.

Crawford provides the same explanation in an earlier unofficial tweet in February 2016:

Would the movement caused by a failed save on Dissonant Whispers be willing or unwilling movement?

If a spell forces you to move, as dissonant whispers does, you're not moving of your own volition.

Does that mean the movement from Dissonant Whispers doesn't provoke opportunity attacks?

The movement in dissonant whispers can provoke opportunity attacks, since it uses your reaction (PH, 195).

The same logic would follow here regarding infestation and booming blade; the spell is forcing the targeted creature to move, so the creature is not doing so willingly. Thus, booming blade's extra damage would not trigger.

(Sidenote: infestation does not trigger opportunity attacks either, because it moves the creature without using its action, reaction, or movement.)

\$\endgroup\$
3
\$\begingroup\$

No

As you said, booming blade requires willing movement:

If the target willingly moves before then...

"Willingly" means:

readily; of one's own free will.

However, this movement is a result of infestation forcing the creature to move regardless if they fail their save.

The target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move and its speed is at least 5 feet.

Here's the thing: the creature has no option to decide if (or even where) they want to move. Therefore it is absolutely not "of one's own free will"; rather it is a textbook example of being forced to do something, which is quite the opposite.

Rules as Intended support

Jeremy Crawford supports this view:

Booming blade hurts you if you move away willingly. Dissonant whispers forces you to move—doesn't trigger BL.

Dissonant whispers is a spell that, like booming blade, forces movement on a failed save. Thus it is a very applicable comparison and the ruling is transferable.

He also somewhat more indirectly supports this further when he says:

A push is an effective way to force a creature to enter an area of effect, unless it requires willing movement.

A push/shove is another way to make an opponent move similar to this spell. Once again the creature has no choice in the matter and, as a result, Jeremy Crawford says that the movement is not willing. I think the situation is very analogous to the one in your question.

\$\endgroup\$
1
\$\begingroup\$

No.

As you quoted,

If the target willingly moves

Infestation forces a saving throw, imposing damage and movement.

The target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move and its speed is at least 5 feet.

This is pretty clear indication that Infestation's movement is forced, not willed, and therefore does not trigger Booming Blade.

\$\endgroup\$
  • \$\begingroup\$ It also doesn't utilize movement on their turn. THey're not even using their own movement in the traditional sense. \$\endgroup\$ – NautArch Jun 21 '18 at 19:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.