Cave In 7/16
Reduces one target's HP to 25% of its current amount and causes Sap. It is unblockable, but it will fail on targets immune to instant death.
Causes instant death to one opponent. Its Hit Rate is 100, and it will fail on targets immune to instant death. It works against the undead, and stalls final attacks for one turn.
13/16 chance of either heavily damaging a unit or plain killing it. It's not great against bosses, but I usually don't dance against bosses (unless it's a boss that snare can insta-kill)
You know, I don't trust FFVI's programming enough to know whether Snare actually causes Death instead of whatever Final Fantasy's equivalent to Expel is (I think X-Zone is the same way which causes the player to miss out on the reward of the Wrexsol fight if they use it instead of
doing it the hard way
using one of the other Insta Death tricks like Vanish Doom). I.E. Snare costs you the reward of any enemy it removes. That said, Snare doesn't work on aerial enemies (of which there are plenty) either way.
And I believe that Cave in only does 1/2 total HP worth of damage (not like this matters since you can probably two shot most WoB enemies by the time you encounter them anyways and by WoR you have better options like the Setzer + Offering + Fixed Dice combo or level 3 spells).
Either way, this is all academic given that the loss of control alone renders the Dance command all but useless (although I have gotten good mileage out of Wind Song during the fight against the IAF since the healing is still good, plus free and steady, and wind damage is hard to come by).