The spell Black Tentacles (listed as Evard's Black Tentacles on PHB p. 238) has the following text:
When a creature enters the affected area for the first time on a turn
or starts its turn there, the creature must succeed on a Dexterity
saving throw or take 3d6 bludgeoning damage and be restrained by the
tentacles until the spell ends. A creature that starts its turn in the
area and is already restrained by the tentacles takes 3d6 bludgeoning
damage.
Each of the two sentence has a condition that results in damage. Note that there is no "or" or "instead" in the second sentence. The second condition is more specific than the first, but it never says they're exclusive.
Does this mean a creature starting its turn restrained by the tentacles receive the damage twice?
Best Answer
My reading of the spell is that it is poorly worded, and that the two scenarios:
and
are intended to be two alternatives for reaching the damage condition, even though they overlap on a reasonable strict reading of the text.
The power disparity with other area-affecting damage spells of the same level is due to the restrained condition leading to auto-damage, whilst other similar area control plus damage spells do not prevent moving away, just encourage it. There is no need (and it seems too powerful) to re-apply the first saving throw plus damage to a creature that is triggering the second condition.
I would actually change the first sentence to:
Now clearly that is not RAW, and I have no indication from other sources that this is a correct interpretation. However, I think the argument from game balance is a strong one. Note this can still lead to a creature becoming restrained and taking the damage twice in a round, if for instance it is pushed into the area of the spell on another creature's turn.
This is how we play spell in my group, and it is still a preferred spell for 7th level Wizards.