War Caster + Sentinel + Lightning Lure/Thorn Whip

[TheRedTemplar]

Using the above combination of feats and spells, I expect the following would be what happens:

>Enemy tries to escape, triggering an Attack of Opportunity even if they disengage
>War Caster allows me to use Lightning Lure/Thorn Whip instead of using a normal attack
>I hit/they fail the saving throw, and are pulled 10 feet back towards me. Their speed also becomes 0 for the rest of the turn, so they can't try to escape again
>They take damage from the spell

Is this correct, or did I make a mistake?

[RickAllison]

Unless you intend to use it with something with reach, it is kind of redundant. OAs interuupt the movement so Sentinel stops them while they are still in your reach.

[DivisibleByZero]

Is this correct, or did I make a mistake?

AFB, but unless I'm misremembering:
Made a mistake.
War Caster allows you to cast a spell instead of making an OA.
This means their speed is not reduced to 0 anymore. Sentinel's benefits no longer apply.

[Joe the Rat]

It might matter if you have a polearm - you've got the expanded limit, so pulling them back close could be useful.

If DivisibleByZero is right (also afb), then there are some spell alternatives (booming blade, hold person, tasha's hideous laughter, disintegrate), but in that case, you might as well just hit them.

They are disengaging, which means they only get one less potential move. That -10 feet from Ray of Frost suddenly becomes more important.

Or, y'know, hit them.