Hey DM’s, I’m running Lost Mine of Phandelver / Phandelver and Below for a group of players. 3 new to D&D and 1 a veteran. All family. I wanted to give them more encounters of iconic monsters and thinking of introducing a Gelatinous Cube in W2: Mine Tunnels in Wave Echo Cave. I would be replacing the Ochre Jelly with the Cube.
The terrain has low ceilings so medium and large creatures have disadvantage with melee weapon attacks unless it’s a small weapon.
That being said, how would an encounter with a cube actually go? I would presume traditional hack and slash with ranged and melee weapons would be pretty much useless against the cube. An attack with a sword would be like running a knife through Jello. An arrow would just get absorbed. Should the cube really take damage on those hits? I would imagine you run or hit it with spells or some other sort of splash damage. What does everyone do about this?
Run it exactly as it is in the book. It takes damage as normal. Even at CR 2, Gelatinous cubes are really deceptively hard for low level characters. If the players are new and don’t realize they need to pull out engulfed characters, it can essentially 1-shot some characters, even at level 4-5 where they’ll be in wave echo cave.
The archetypical gelatinous cube encounter is "PCs are walking down a passageway and walk into a gelatinous cube" (see its Transparent trait). At a DC of 15, there's a good chance of a PC with at least that much passive perception, but if something is causing disadvantage (say, PCs relying on darkvision, or you just decide to give them disadvantage because it's an inconvenient area), or the marching order is such that the person leading the way does not have sufficient perception, they can attempt to walk into the cube (being automatically subjected to its engulf action, with disadvantage on the save), and then the cube gets a surprise round, uses its engulf action again, and runs over the rest of the party. Given that it's a Dex save DC of 12 and a lot of PCs have decent dex and/or save proficiency, on average it doesn't engulf very many people... but with some unlucky rolls it can be an extremely dangerous encounter.
A gelatinous cube takes damage normally. It's low AC with such CR makes up for the stronger traits, actions and damage it does. If you place it in a terrain where low ceiling cause medium and large creatures to have disadvantage with melee weapon attack, it should be an even bigger challenge for the party than it already is as they may have harder time hitting it, while it's most powerful main action doesn't involve attacking when the cube Engulf creatures.
Another easier option could be 6 foot high ceiling causing the cube to be Squeezing into a Smaller Space but otherwise don't affect characters attack, or possibly only those with bigger weapons such as greatsword, halberd etc.. This would also limit how far the cub moves.
Squeezing into a Smaller Space
A creature can squeeze through a space that is large enough for a creature one size smaller than it. Thus, a Large creature can squeeze through a passage that's only 5 feet wide. While squeezing through a space, a creature must spend 1 extra foot for every foot it moves there, and it has disadvantage on attack rolls and Dexterity saving throws. Attack rolls against the creature have advantage while it's in the smaller space.
Hey DM’s, I’m running Lost Mine of Phandelver / Phandelver and Below for a group of players. 3 new to D&D and 1 a veteran. All family. I wanted to give them more encounters of iconic monsters and thinking of introducing a Gelatinous Cube in W2: Mine Tunnels in Wave Echo Cave. I would be replacing the Ochre Jelly with the Cube.
The terrain has low ceilings so medium and large creatures have disadvantage with melee weapon attacks unless it’s a small weapon.
That being said, how would an encounter with a cube actually go? I would presume traditional hack and slash with ranged and melee weapons would be pretty much useless against the cube. An attack with a sword would be like running a knife through Jello. An arrow would just get absorbed. Should the cube really take damage on those hits? I would imagine you run or hit it with spells or some other sort of splash damage. What does everyone do about this?
Run it exactly as it is in the book. It takes damage as normal.
Even at CR 2, Gelatinous cubes are really deceptively hard for low level characters. If the players are new and don’t realize they need to pull out engulfed characters, it can essentially 1-shot some characters, even at level 4-5 where they’ll be in wave echo cave.
The archetypical gelatinous cube encounter is "PCs are walking down a passageway and walk into a gelatinous cube" (see its Transparent trait). At a DC of 15, there's a good chance of a PC with at least that much passive perception, but if something is causing disadvantage (say, PCs relying on darkvision, or you just decide to give them disadvantage because it's an inconvenient area), or the marching order is such that the person leading the way does not have sufficient perception, they can attempt to walk into the cube (being automatically subjected to its engulf action, with disadvantage on the save), and then the cube gets a surprise round, uses its engulf action again, and runs over the rest of the party. Given that it's a Dex save DC of 12 and a lot of PCs have decent dex and/or save proficiency, on average it doesn't engulf very many people... but with some unlucky rolls it can be an extremely dangerous encounter.
A gelatinous cube takes damage normally. It's low AC with such CR makes up for the stronger traits, actions and damage it does. If you place it in a terrain where low ceiling cause medium and large creatures to have disadvantage with melee weapon attack, it should be an even bigger challenge for the party than it already is as they may have harder time hitting it, while it's most powerful main action doesn't involve attacking when the cube Engulf creatures.
Another easier option could be 6 foot high ceiling causing the cube to be Squeezing into a Smaller Space but otherwise don't affect characters attack, or possibly only those with bigger weapons such as greatsword, halberd etc.. This would also limit how far the cub moves.
This helps a lot! Thanks everyone.