Thanks a lot to everyone who has commented. Very useful to see different approaches to designing this. After several failed attempts, I finally hacked together a version of a garrote that I
think is balanced or at least moving towards balance...
Garrote 5 gp, 1 lb.; 1d6 bludgeoning damage; Finesse, Two-handed, Special
Restrictions: A garrote can only be used on a creature your size or smaller against which you have advantage on the attack roll. You can only make one attack with a garrote on your turn.
Effect: On a hit, the target is grappled. Until this grapple ends, the target is forced to hold its breath and it cannot make sounds louder than a whisper. The escape DC is 8 + your proficiency bonus + your STR/DEX modifier, whichever you used for the attack.
Maintain: In order to maintain the grapple with the garrote, you must use two hands and you must use your action to keep the target grappled. Each time you use your action in this way, the target takes 1d6 + your STR/DEX modifier damage, whichever you used for the attack. If you use your action to do anything besides maintain the grapple, or if you are unable to take an action, then the target is no longer grappled.
Surprise: However, if the target is surprised, the garrote has far greater efficacy. On a hit against a surprised target, not only is the target grappled, but it cannot breathe (i.e. it starts suffocating) and it cannot speak. Maintaining these additional effects requires you to sustain concentration (like spellcasting); if your concentration is broken, the grappled target is no longer suffocating and can speak in a whisper. Otherwise, it is resolved exactly as above.
Here's my reasoning:
- It's "your size or smaller" and not "Medium or smaller" because you might be a gnome/halfling or you might get enlarged!
- You cannot use garrote to make an opportunity attack, because it must be used on your turn.
- You cannot use Extra Attack or Action Surge to make 2+ garrote attacks, nor can you dual wield garrote and shortsword (since it's two-handed). If you miss, then the opponent realizes what you're up to and that limited window to garrote is gone for the moment. If you hit, well, you can't really make any more attacks cause your hands are tied up choking that hobgoblin out.
- The hit triggers the automatic grapple. Hitting with a garrote, only to deal damage but not initiate a grapple is... that's just jarring narratively, it wouldn't make sense.
- The baseline effect gives the target minutes of air and still allows it to cast spells, use command words, and such. • The escape DC is not linked to skills, thus mitigating any abuse – typically PCs will get much higher skills than monsters ever will.
- The maintained automatic damage dealt by the garrote is not an attack. The idea being that a rogue could use Sneak Attack on the initial attack, but not for anything while the target is holding their breath (or suffocating). This is because if I/we end up sticking with that Taking Damage While Holding Breath house rule (or some version of it), Sneak Attack auto-damage every round could wipe out pretty much any creature's held breath.
- The surprise effect has 2 parts. First, the suffocation is brought in because, well, typically if you have a surprise round then that enemy is going to go down hard or be fighting on the defensive, and combat is going to be fairly short. Like 1-3 rounds, which is probably how many rounds before the target suffocates into unconsciousness.
- The second part of surprise is silence. This is basically similar to a single target version of the 2nd level silence spell – hence the use of the concentration mechanic!