The gelatinous cube possesses the extraordinary ability engulf that says

Although it moves slowly, a gelatinous cube can simply mow down Large or smaller creatures as a standard action. It cannot make a slam attack during a round in which it engulfs. The gelatinous cube merely has to move over the opponents, affecting as many as it can cover. Opponents can make opportunity attacks against the cube, but if they do so they are not entitled to a saving throw. Those who do not attempt attacks of opportunity must succeed on a DC 13 Reflex save or be engulfed; on a success, they are pushed back or aside (opponent’s choice) as the cube moves forward. Engulfed creatures are subject to the cube’s paralysis and acid, and are considered to be grappled and trapped within its body. The save DC is Strength-based and includes a +1 racial bonus. (Monster Manual 203)

Can an answer walk me through the turn of a gelatinous cube that wants to use this special ability?

I mean, so it's the cube's turn and the cube takes a move action to get nearer its foes then it takes a standard action to… do what exactly? Does it take that standard action to continue moving into the occupied squares of as many foes as its 15 ft. speed allows, potentially engulfing every foe in its path with no maximum as to the number of creatures that can be engulfed? (And hilarity ensues!) Does it take that standard action to engulf but one adjacent creature by moving into that creature's space and covering the creature, a result that seems disputed by the description of the engulf ability? Or does something else happen that I'm totally overlooking?

Note: The last cube I ran was a Gargantuan cube advanced to 24 Hit Dice partnered with a Huge advanced Monster Manual mimic (186) in a high-level adventure. However, the pair just hit and grappled foes, the cube never engulfing. While doing some reading, I was pointed at the ninth and final issue of the ex-Wizards of the Coast messageboard-sponsored Knowledge Arcana PDF e-zine that includes the prestige class adamantine chef. (For those interested, previous Knowledge Arcana issues are available by changing that issue #9 URL from 09.PDF to 08.PDF and so on, and also available is the nominal 3.5 update of the pie fiend that's issue #9's PDF Web extra.) Included in the prestige class article is a new monster that can be summoned by the adamantine chef: the death salad (I'm not even kidding)… that has the same special ability engulf as the cube. In trying to summarize the death salad's engulf ability for personal use, I realized I had no idea how the ability worked and that the cube's ability worked in an identically baffling fashion.

Also, while several 5e questions have been posed about the cube's engulf ability, only this one is really about the 3.5e cube and its engulf ability, but it's about how much damage the cube deals after it's engulfed a hapless foe rather than how the engulf ability works.


It engulfs whoever it moves over with its 15 foot movement.

Your gargantuan cube is 20 feet wide- if it moves directly forward for 15 feet it will engulf anyone standing in the 20 x 15 foot area directly in front of it - potentially 12 medium sized creatures.

  • \$\begingroup\$ So it spends both its move action and its standard action simultaneously—like a full-round action in all but name—to engulf everything in its 15-ft. path? Or it can first take a move action to move then can take a standard action during which it can both move and engulf everything in its second 15-ft. path? \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 5:08
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    \$\begingroup\$ There is nothing in the text to suggest that the standard action described gives any extra movement so, yes, the move and engulf actions are simultaneous \$\endgroup\$ – Dale M Dec 25 '17 at 5:12
  • \$\begingroup\$ It'd be great if this answer walked me through the turn of a gelatinous cube that wants to use this special ability. I mean if the mechanics really are On its turn the cube simultaneously takes a move action and a standard action to move 5 ft. and over 2 Medium creatures and attempts to engulf them then 10 ft. and over 1 Large creature and attempts to engulf it. Success on all engulf attempts leaves all 3 creatures within the cube that's cool and hilarious and all, but a little more detail to beef up this answer would be awesome. \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 5:21
  • \$\begingroup\$ Also, doesn't the first line of the special ability's description suggest that movement is part of this standard action? That is, it says, "Although it moves slowly, a gelatinous cube can simply mow down Large or smaller creatures as a standard action," not mentioning that a move action is also necessary to mow down potential snacks. \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 5:46

The move action and the Engulf's standard action are separate.

By virtue of the comment:

"The gelatinous cube merely has to move over the opponents, affecting as many as it can cover"

...it is apparently allowed to move into the spaces of opponents. If any creatures it wants to engulf is in the covered space at the end of it's move, it can then take a standard action to engulf whatever creatures are in the target area. (By changing the permeability of it's membrane, maybe?) If they succeed on the reflex save, they are instead pushed back or to the side (opponent's choice).

Creatures that fail are now "engulfed" and are thus in a legal positioning at the end of the cube's turn. Creatures that succeed on the save are "pushed back or to the side", and are also thus in a legal positioning at the end of the cube's turn.

Should it not choose to engulf, then it would be subject to the standard movement rules and have to end it's turn in a legal space.


  1. Cube's turn.

  2. Cube decides to take engulf action during it's turn as snacks are in range.

  3. Cube takes move action. This move may end in squares overlapping opponents if and only if it is going to take an engulf action during this turn. This movement will trigger AoO's only if the movement would normally trigger by the AoO rules.

  4. Cube takes standard action to activate engulf. This triggers the option for Reflex save OR AoO per the Engulf ability, which may have nothing to do with movement triggered AoOs.

  5. Everyone ends up either inside the cube taking damage, or pushed back or aside to a legal position and not engulfed.

  6. End of Cube's turn.

  • \$\begingroup\$ Can you walk me through the cube's turn? The cube takes a move action and ends its move in one or more squares occupied by foes then the cube takes a standard action to engulf those foes. It doesn't provoke for just moving into those squares during its move action and it can end that movement in those occupied squares prior to the engulf. Is that right? \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 18:48
  • \$\begingroup\$ @HeyICanChan Okay, added what I think would be the proper chain of events. \$\endgroup\$ – nijineko Dec 25 '17 at 19:06
  • \$\begingroup\$ O, my… so the presence of a cube creates in the game the need for a declare phase? \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 21:18
  • \$\begingroup\$ @HeyICanChan pretty much just like the facing rules. ^^ I suppose we could look at it as if it moves into others' spaces, then it has to engulf rather than slam and avoid the declare concept, or rather instead of a declare phase per se, it's more of a meta-declare phase, as (usually) only the DM will be playing a gelatinous cube. I guess they just somehow magically expect DMs to know the rules or something. \$\endgroup\$ – nijineko Dec 26 '17 at 2:13

As far as I can tell, gelatinous cube's Engulf ability is a successor of Trample ability. You may probably reffer to Trample for every aspect not covered by Engulf's own description.

First of all, Trample was changed between D&D 3.0 (and gelatinous cube already was there) and D&D 3.5. Back then in D&D 3.0 Trample worked mostly like Engulf works now.

So a turn of a cube would look like:

  1. It may choose to use its move action to close up if necessary.
  2. Engulf itself provides a portion of movement equal to a cube's land speed.
  3. While Engulf specifies "large or smaller opponents", the description most probably intended to say "same size or smaller opponents". When the cube uses Engulf it may "mow down" everybody whose space it passes through during its movement gained from Engulf given those creatures are of a valid size.
  4. If it for some reason hasn't already used it's move action, it may now use it taking everybody it engulfed with it.

It is my assumption, but gelatinous cube may not probably simultaneously engulf more opponents than it can cover with it's space (i.e. their spaces have to be able to be housed inside its space).

You may also consider to rework Engulf special ability to match new mechanic of Trample, but it is utterly up to you.


I read the first part of the description as "As a standard action, the cube moves over some opponents and engulfs them".

This means that the cube also gets a regular movement action.

  • \$\begingroup\$ Please, walk me through the typical cube's turn. So, during the standard action the cube both moves and engulfs and—before or after—it can also take a move action? \$\endgroup\$ – Hey I Can Chan Dec 25 '17 at 21:20
  • \$\begingroup\$ @HeyICanChan that's my reading. Being Engulf a standard action, it can be taken whenever a standard action could be taken. A "typical" turn i not really indicative of the capabilities of the cube. Please note that moving while in a grapple is harder, and the cube is considered to be grappling engulfed foes. \$\endgroup\$ – Zachiel Dec 26 '17 at 11:31
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    \$\begingroup\$ Fair enough. But RE: "[T]he cube is considered to be grappling engulfed foes." The ability says, "Engulfed creatures are subject to the cube’s paralysis and acid, and are considered to be grappled and trapped within its body." This makes it sound like (to me anyway) while the engulfed creatures are considered grappled, the cube isn't actually grappling, so the cube can continue moving normally despite the presence of nigh-infinite orcs, struggling for freedom from their mobile cube prison. \$\endgroup\$ – Hey I Can Chan Dec 26 '17 at 11:51

I have always interpreted the rules such that:

  1. Engulf is a standard action.

  2. The Gelatinous Cube (GC) must have enough movement to occupy at least one square that contains another creature (Large size or smaller) without taking more than one move action.

  3. If the GC uses its movement to occupy 1 or more creatures square(s), then it has to use its standard action to make an Engulf attack. Otherwise, it would not be able to occupy another creature's square.

  4. Creatures that could potentially be engulfed have the option to make an AoO, but are automatically engulfed in the GC, if the GC survives the AoOs.

  5. If the GC uses two move actions to occupy the PC's square, the GC would not be allowed to engulf this round. If it is still sharing any squares with another creature at the start of its next turn, it will immediately try use an Engulf attack.

The Engulf action does not grant any extra movement, but is automatically activated when its movement ends in one or more occupied squares.


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