fluffybunbunkittens
Hero
By the rules, any forced movement breaks the grapple. Doesn't necessarily make sense, but neither does grappling a gelatinous cube to prevent it from engulfing you, yet there it is.
Thunderwave is a spell of "instantaneous" "thunderous force" capable of blasting targets.
Levitate can be interpreted as just making "one creature or loose object" weightless while also facilitating a 20 ft per six seconds, and (per spell description) very arrestable, average speed. If the creature itself applies force, it can move itself. What happens if another creature applies the force?
There's no thunder. This what the title wording of spell indicates that it does.
View attachment 287989
What if something with weight prevents the movement?
OK. Despite the wording:Like I said, I'd give the grappler a saving throw to hold on to the target. If the grappler succeeds on the saving throw and the combined weight is more than 500 pounds then neither of them are levitated, although the spell is still pulling the target up. But I don't see much difference, in either case there is a force that is moving the grappler and the creature being grappled apart. No different from someone else trying to pull the grappled creature from the enemy's grasp.
The rules can't cover every scenario, I'm just relaying my ruling.