Water Weird Attack Weirdness

Question

My players fought a water weird last night, and its attack as written on page 299 of the Monster Manual is rather complex. First, you make a roll as normal and do bludgeoning damage.

If the target is Medium or smaller, it's grappled so its speed becomes 0 and it has all the other effects of that condition. The target is also pulled 5 feet towards the water weird.

While the grapple is in effect, the target is also restrained. The effects of that condition are the target's speed becomes 0, which is redundant with being grappled, the creature has disadvantage to hit, but advantage to be hit, and the creature has disadvantage on Dexterity saves. Also, the water weird's grapple includes the notation "...(escape DC 13)...". However, the rules for escaping a grapple are that a contested check must be made, not that a specific DC needs to be reached.

The next part is where the problem comes in. The text says "...the water weird tries to drown it, and the water weird can't constrict another target." From what I can find in the PHB and DMG, drowning uses the suffocation rules. Those state that a creature can hold its breath for 1 + Con modifier minutes (minimum of 30 seconds), then can survive an additional number of rounds equal to its Constitution modifier before it starts dying.

So, a water weird facing an adventuring party hits one of the players and grapples/restrains/begins drowning it. That player has, at the very least, 5 combat rounds (the minimum 30 seconds) to try to escape. However, during that time, the water weird has no other action to take because it can't constrict another target, and the rest of the party can hit it with whatever they want.

Am I understanding this correctly, that the water weird (if it hits) is pretty much a one-shot monster? What's going on with the specific DC to escape the grapple, rather than using the standard rules?

Answer 1

The important part of that attack option is this:

And the water weird can't constrict another target

This same terminology is used of creatures like the Tarrasque who have the 'Bite and Swallow' feature or a Kuo-Toa Whip's Pincer Staff.

This means that the Weird cannot Constrict any target other than the one that it is presently constricting. So it can repeat this attack against the same target every round, in addition to the fact that you are being held underwater. Most likely, it will kill you by crushing rather than killing you by drowning.

In fact, the lore comments on it even makes it clear that it is trying to crush you.

[...] using its coils to crush any creature other than its summoner [...]

One other point of note when fighting a Water Weird: It has a 10' reach, and can fight just fine in deep water. The party may have a difficult time reaching it if it is sitting in water too deep to stand in. This can make it a little extra challenging as well if the party has to jump in and try to swim in order to fight it in melee.

Answer 2

On the monster manual, page 11 you can find the special grapple rules for monsters which explain why a DC is provided for grapples performed by monsters.

As for the Water Weird's constrict limitation, note that there is nothing stopping it from using constrict repeatedly on the same target every turn.

While it is true that drowning takes a while and a creature is unlikely to be killed by drowning during combat, the grappled (and restrained) creature is likely to continue to take damage every turn since as you noted, the Water Weird now has advantage when attacking it.

Answer 3

As other answers mention, monsters have special grappling rules, and the water weird can attack the restrained target.

This effectively means by taking itself "out of the fight" it can take another creature out of the fight. Not very dangerous if 1 WW is fighting a party of 5 Adventurers, but bear in mind this creature is invisible in a body of water. This makes it great as an addition to an encounter. Imagine you enter the inner sanctum of a Temple to Lloth, and as your party engages the Drider guards and starts to deal with the High Priestess herself, the "unholy water" in the font by the door comes alive and swallows your wizard, slowly drowning and beating him to death. Not bad for a CR 3 monster (considering the party in this example is likely lvl 6+). Even if he only manages to grapple/distract the wizard for a couple rounds, that's more than enough to change the balance of the fight.

Think of them as Controllers more than Tanks or Strikers.