D&D 5E OotA: Thorn Whip and Glabbagool

[Werebat]

So I'm running OotA and the party met Glabbagool. They got to be friends and they seemed willing to slow down for the cube so it could follow them.

Then the party underdark druid got the bright idea of trying to use Thorn Whip to pull enemies into Glabbagool.

Thorn Whip has been an incredibly useful cantrip from the very first session, when it snapped an elite drow off a web bridge and let it drop to the spider webs below. I think it's a cool idea to use it to yank enemies into Glabbagool, but am wondering how to adjudicate it.

I'm thinking that there would likely be some cover penalties to hit in most cases, despite the spell acting like a melee weapon with reach. You can't use the reach of a polearm to strike through a stone wall without penalty. If snapped into Glabbagool, an enemy would get a Dex save similar to if Glabbagool had slid forward to engulf them. Success would leave them one square outside of the cube.

Sound reasonable? Anyone else had this come up in their OotA campaign?

 

[MonsterEnvy]

Make sure they eventually realize that slowing down for the cube will allow the drow to easily catch up with them.

 

[Oofta]

How is the druid getting around Glabbagool? I don't have the mod, but isn't he a large, solid cube that would grant total cover? Since the thorn whip only pulls 10 feet, I'm having a hard time how your druid could pull someone into it.

At the very least, he'd have to be behind the cube, lean out and pull someone in ... but that would at least three-quarters cover.

In addition, sooner or later the drow are going to learn what's going on and deal with it by staying away from the cube or targeting it first.

 

[Undrhil]

Well, if they avoid the cube, they are avoiding the PCs, so that's a Win. If they target the cube first, then the PCs have some time to run interference.

Honestly, if this is an intelligent creature, as the DM I would have it start resenting the fact that the PCs are only keeping it around to do their dirty work.

 

[Jediking]

Then the party underdark druid got the bright idea of trying to use Thorn Whip to pull enemies into Glabbagool.
I think it's a cool idea to use it to yank enemies into Glabbagool, but am wondering how to adjudicate it.

Does Glabbagool have his own place in combat? If so, you can let the Druid take control of him (ala the Motley Crew) to set up his own combos.
-Glabbagool's turn. Uses Ready to move sideways/Engulf when enemy approaches reach.
-Druid's turn. Uses Thorn Whip to grab enemy and pull towards him (must be standing to the side of Glabba). Glabba's readied action is triggered and works as normal.

Or the Druid can ready his action to Thorn Whip and then control Glabba. It's a really cool idea, so give the player his own power to set it up.

 

[Jediking]

In addition, sooner or later the drow are going to learn what's going on and deal with it by staying away from the cube or targeting it first.

Ah, but that's the brilliance of this combo if no drow escape. The cube leaves no evidence!

 

[RulesJD]

I mean they could literally accomplish the same thing with standard a Grapple, and anything that encourages Druids to do something at lower levels besides dominate in Bear form is a positive, so I say kudos to them for creativity.