Are oozes overpowered for their levels due to the Engulf ability?


Background

Early in my campaign, there was a combat encounter where three level 2 PCs fought a single gelatinous cube. The cube was the standard level 3, and there were no special outside circumstances such as difficult terrain. As per the XP reward and XP budget rules, the cube was worth 60 XP, a Moderate threat encounter for a party of three. The cube proceeded to kill a character and another character’s animal companion.

This week, much later into the campaign, three vaultbreaker oozes (level 6) engaged with a party of four PCs (three 7th level, one 6th level). The PCs were at full health, had no afflictions, and had nearly all of their spells available as this was the beginning of the dungeon. Again, no difficult terrain or extraneous circumstances. Based on the XP reward and budget rules, the encounter would have been worth about 90 XP, a high-moderate to low-severe threat encounter. The oozes caused a total party kill.

The Apparent Cause: Engulf

It seems to me that both of these deadly results were the direct result of the Engulf ability. All deaths occurring from the two aforementioned encounters were the result of accumulated damage from acid and suffocation resulting from the oozes’ Engulf usage.

Some things to note about Engulf:

  • The ability is unlimited in use. There is no cooldown. An ooze can use it every round (and it seems likely that oozes would, based on my interpretation of oozes’ main goal of mindless consumption).
  • The ability only costs two actions and is not itself a Strike, which means a Strike can be used before or after Engulf at no multiple attack penalty.
  • The ability doesn’t require the ooze to move in a straight line — it merely states that the monster Strides up to double its Speed, meaning that it can turn and twist during its movement, allowing it to effectively "roomba" up a large area by sweeping itself around.
  • I don’t see a limit to how many creatures can be Engulfed by a single ooze, but to me it seems reasonable that a large creature like a gelatinous cube or vaultbreaker ooze would be able to engulf up to four medium-sized creatures, since they’d all fit in its area.
  • Engulfed creatures are pulled into the ooze’s body and are grabbed, which I interpret as meaning that they remain in the ooze’s body as it moves, including the continuation of the Engulf’s double Stride.
  • Though the Engulfed creature can attempt to escape, it is Slowed 1 by the Engulf, leaving it only two actions to do something that may be quite difficult for physically weaker characters.
  • Engulfed creatures are subject to suffocation rules.
  • I’m not sure on the rules for this, but it’s possible that non-Engulfed casters are unable to target Engulfed characters with healing abilities, even if the ooze is translucent or transparent. I’ve asked a separate question about this here.

Some things to note about oozes:

  • They often have large HP pools, meaning it’s tough to kill one quickly if it’s Engulfed your ally.
  • They are immune to critical hits, so double damage isn’t applied even though crits happen often with oozes’ typically low AC.
  • They are mindless feeders, so it’s hard for a GM to come up with a reason that they wouldn’t finish a PC or party off — assuming the PC or party hasn’t been engulfed before or after the PC or party was defeated, which probably would be the case.

How It Happens

  1. The PC is Engulfed.
  2. The PC takes acid damage from the Engulf at the end of their turn, every turn.
  3. The PC can’t breathe and is subject to suffocation.
  4. The PC eventually hits Dying 1. At this point, the PC can no longer hold their breath since they are unconscious, and therefore become subject to suffocation damage if they weren’t out of breath already.
  5. The PC’s next turn ends, at which point the PC hits Dying 2 as a result of the acid damage, and possibly Dying 3 in the same turn if the PC fails their fortitude save against suffocation.
  6. The PC saves against death, possibly dying.
  7. If the PC survives, they can gain another 2 points of Dying easily next turn due to the acid and possible suffocation damage.
  8. And so on.

As you can see, the combined effects of Engulf can quickly kill. Suffocation is pretty deadly as is, but Engulf takes it to a whole other level.

Are oozes improperly balanced, or am I doing something(s) wrong?

It seems to me that oozes’ threat is far too high for their given levels. Am I running oozes wrong, or is this a balance issue with the system?

ADDENDUM: As a wise commenter pointed out, the third option is that my players are simply suffering the results of not treating oozes as the special case/danger they are, and should have taken special precautions against them (especially since my players have 15+ years of gaming experience and knew the dangers of oozes in both Pathfinder 2e and other systems). This is a definite possibility, and I’m happy to receive answers related to this.