What if a creature with a burrowing speed grapples a player, drags them underground, then leaves them there?

Quote from jl8e >>

 

Regardless, of RAI, RAW is that Tunneller is restricted to Speed. No rush jobs here (and wear your PPE).

If you're going to go for strict RAW, it is a separate ability in addition to the creature's normal move. It requires no action or bonus action. The frequency of use is... unclear. Movement abilities specify that they use the creature's move. Tunneler doesn't, so it's not.

Uhm ... fair, I guess. It should consume movement or be an action (or both).

Quote from SmiteMakesRight_3_5 >>

Quote from jl8e >>

 

Regardless, of RAI, RAW is that Tunneller is restricted to Speed. No rush jobs here (and wear your PPE).

If you're going to go for strict RAW, it is a separate ability in addition to the creature's normal move. It requires no action or bonus action. The frequency of use is... unclear. Movement abilities specify that they use the creature's move. Tunneler doesn't, so it's not.

Uhm ... fair, I guess. It should consume movement or be an action (or both).

 Exactly. If you try to parse it out on strict RAW, you get this thing, neither fish nor fowl, that doesn't work.

If you look at it and say "what's this supposed to be?", it's a movement ability. If you treat it like every other movement ability, it works fine.

Tunneler is not an Action letting an Ankheg move whatsoever, its a Trait active anytime it burrow through solid rock.

"burrow through solid rock at half its Burrow Speed" I take it to mean it has a Burrow Speed 10 ft but 5 ft. through solid rock. 

Trait: Monster characteristics that are active at all times or during certain situations appear here.

Creatures typically can't burrow through solid rock but some Tunneler trait essentially mean; 

Burrow Speed: A creature that has a Burrow Speed can use that speed to move through sand, earth, mud, or ice. The creature can’t burrow through solid rock unless the creature has a trait that allows it to do so. at half its Burrow Speed.

Quote from SmiteMakesRight_3_5 >>

TarodNet quoted the Dash rule. Tunneller lets you create tunnels with a length equal to half your speed. Dash gives you increased movement equal to your Speed but does not increase your Speed itself. So, it helps you burrow further in a turn but not tunnel further.

I have to agree with @Plaguescarred.

The Tunneler trait doesn't give you a new ability, it is an extension of your Burrow Speed that lets you use that speed (at a reduced rate) in a place where having a Burrow Speed normally doesn't work. So if you have a 50ft Burrow Speed you could burrow through 25ft of solid rock and then Dash to burrow for 25ft more.

It then also says that you leave a tunnel behind. But that's just an effect of you having moved through that space, it is not some sort of separate special action you take to make tunnels.

Quote from jl8e >>

Quote from SmiteMakesRight_3_5>>

It would have been a simple enough change to say: "The [creature] can burrow 1 foot through solid rock for every 2 feet of Burrow movement and leaves a [size]-foot-diameter tunnel in its wake." It takes up slightly more space, though.

Or several other phrases. Nonetheless, we all know what it means. They wrote a bad template.

I do agree that it could have been better worded. I would probably have used something like "burrow through solid rock as if it were difficult terrain" as that is a well known and used movement modifier.